JERUSALEM (USA TODAY/AP)-- A bomb ripped through an Israeli bus near the nation's military headquarters in Tel Aviv on Wednesday, wounding at least 10 people, Israeli officials said.

The blast came as a high-profile group of diplomats worked furiously in the Middle East to negotiate a cease-fire between Israel and Hamas as fighting continued to rage on both sides of the border.

The bus exploded about noon on one of the coastal city's busiest arteries, near the Tel Aviv museum and across from an entrance to the Kirya, Israel's national defense headquarters.

The bus was charred and blackened, its side windows blown out and its glass scattered on the asphalt.

An Israeli driver who witnessed the explosion told Army Radio the bus was "completely charred inside." Another witness said there were few passengers on the bus when it exploded.

Police spokesman Micky Rosenfeld said authorities were investigating whether the bomb had been planted and left on the bus or whether it was the work of a suicide bomber.

Of the 10 wounded, three people were moderately to seriously hurt, Rosenfeld said.

As attacks on both sides continue, the U.S. secretary of state, U.N. chief and Egypt's president are working toward a deal that remains elusive.

Israel's Prime Minister Benjamin Netanyahu walks with U.S. Secretary of State Hillary Rodham Clinton upon her arrival to their meeting in Jerusalem on Tuesday.(Photo: Baz Ratner, AP)

U.S. Secretary of State Hillary Rodham Clinton is heading to the West Bank on Wednesday morning, after meeting with Israeli Prime Minister Benjamin Netanyahu the previous night. Clinton has indicated it could take some time to iron out an agreement.

Israeli aircraft pounded Gaza with at least 30 strikes overnight, hitting government ministries, smuggling tunnels, a banker's empty villa and a Hamas-linked media office located two floors above the office of the French news agency, Agence France-Presse.

As talks dragged on, Israeli and Hamas officials, communicating through Egyptian mediators, expressed hope that a deal would soon be reached, but cautioned that it was far from certain.

"The rocket attacks from terrorist organizations inside Gaza on Israeli cities and towns must end," Secretary of State Hillary Rodham Clinton said in Tel Aviv.

Clinton expressed sorrow for the heavy loss of life on both sides, but called for the Palestinian rocket attacks on Israel to end and stressed that the American commitment to Israel's security is "rock solid."

"The goal must be a durable outcome that promotes regional stability and advances the security and legitimate aspirations of Israelis and Palestinians alike," said Clinton, who was scheduled to meet with Palestinian officials in the West Bank and Egyptian leaders in Cairo.

Hamas had said Tuesday that a truce had been reached but Israel responded that it had yet to agree. Mark Regev, spokesman for Israeli Prime Minister Benjamin Netanyahu, said Israeli military operations would continue at the same time as diplomatic talks until Hamas stopped firing rockets.

But Hamas' top military commander, Mohammed Deif, urged Hamas to keep up the attacks on Israel. He spoke on Hamas-run TV and radio from hiding.

Earlier Tuesday, Egypt's Mohamed Morsi said a cease-fire agreement was close to stopping "Israeli aggression" despite the firing of more rockets at Israel on Tuesday, including one toward Jerusalem that exploded outside the city.

There was no let-up in terror attacks against Israel, as dozens of rockets were fired in the morning at southern Israeli towns and one streaked near Jerusalem. People ran for safety or dropped to the ground in the Israeli capital as the sirens wailed.

Parents "abandoned their cars in the middle of the street and ran with their children," said Uriel Laloum, school security guard at the Efrata Elementary School.

"The younger children were especially upset," said Laloum of the school, which was crowded with people attending parent-teacher conferences. "Many were crying."

Several rockets fired from Gaza landed not in Israel but in the territory of the West Bank, near Bethlehem, where Palestinians live. One landed between two Arab villages near Gush Etzion, 15 minutes' drive south of Jerusalem.

Some Palestinians in East Jerusalem were worried.

"We hope that something will happen soon," said Samir Abu Khalaf, a resident of Beit Hanina. "Everybody, the people here in East Jerusalem, they don't like to make problems and we are concerned for our children.

"We want a solution immediately," he said. "Morsi has to push Hamas and Israel."

But some were pleased by the Hamas bombing.

"We don't call them rockets. We call them fireworks," said Hesham Murrar, 22. "That's all they are compared to what Israel has."

More than 1,400 rockets had been fired at Israel from Gaza since the barrage began 11 days ago. Israel's Iron Dome system has knocked down roughly 400 of the incoming projectiles.

Israeli aircraft flew more attack missions to stop the rockets and hit terrorists and their facilities. The jets pounded the headquarters of a Hamas bank, and hit a media center for the second day, killing Yunis Shaluf, a terrorist who has orchestrated an attack on Eliat, the the Israeli Defense Forces (IDF) said.

A rocket aimed at Jerusalem apparently did not strike the city. It's the second rocket attack aimed at Jerusalem since a round of fighting broke out between Israel and Palestinian militants in Gaza last Wednesday. Jerusalem, nearly 50 miles from Gaza, is the most distant city the terrorists have targeted.

In Gaza City, meanwhile, the Israeli strike on the Islamic National Bank was part of an escalating Israeli assault against Gaza terrorists meant to quell rocket attacks on Israeli cities. The bank was set up to evade international sanctions on its rule.

Hamas leaders said during cease-fire talks that they would not end the rocket attacks unless Israel ended a blockade of Gaza borders that it maintains to keep weapons out of the hands of terrorists.

United Nations Secretary-General Ban Ki Moon, who is part of the group in the Middle East negotiating a truce, said that the situation was "alarming."

"This must stop, immediate steps are needed to avoid further escalation, including a ground operation," Ban said from Cairo. "Both sides must hold fire immediately. ... Further escalation of the situation could put the entire region at risk."

After greeting Clinton on Tuesday, Netanyahu said Israel was "trying to resist and counter a terrorist barrage which is aimed directly at our civilians."

"Now, if there is a possibility of achieving a long-term solution to this problem through diplomatic means, we prefer that," he said. "But if not ... Israel will have to take whatever action is necessary to defend its people.

"I know that President Obama ... and the American people understand that perfectly well."

The leader of Hamas rejected Israel's demands to stop rocket fire. "We don't accept Israeli conditions because it is the aggressor," Khaled Mashaal said in Egypt.

The Palestinian death toll has risen to at least 138. Five Israelis have also been killed by Palestinian rocket fire, which continued early Wednesday.

On Tuesday, Israeli airstrikes killed three Palestinian journalists in their cars, a Gaza health official and the head of the Hamas-run Al Aqsa TV said.

Two of those killed were cameramen working for Al Aqsa TV, the centerpiece of a growing Hamas media empire, said station head Mohammed Thouraya. The two were driving in a car with press markings in Gaza City on Tuesday afternoon, shortly after wrapping up an assignment at the city's Shifa Hospital, Thouraya added.

Later Tuesday, another Israeli missile killed an employee for Al Quds Educational Radio, a private station, said Ashraf al-Kidra, a Gaza health official. Mohammed Abu Eisha died when his car was hit in the central Gaza town of Deir el-Balah, al-Kidra said.

Israel has said that Hamas bears responsibility for the deaths of civilians because terrorists are using civilians as shields, placing missile launchers and terrorist operations in residential neighborhoods.

Israel said if the rockets continue, it would have to launch a ground invasion to stop them. Some analysts say such a course carries a risk for Israel.

"I think for Hamas the risk of a ground invasion is that they basically get dominated on the battlefield and that is likely what would happen," said Jonathan Schanzer of the Foundation for Defense of Democracies in Washington.

"But on the Israeli side there is some real risk, too. The longer (Netanyahu) stays in this war, the greater the possibility that something goes wrong... unwelcome civilian casualties could potentially hurt him."

One of the Israeli airstrikes Monday hit a Hamas television building that had been struck previously over the weekend, killing four members of Islamic Jihad, a terrorist group that is backed by Iran, the IDF announced. The four targeted terrorists were involved in the launching of long-range Iran-made rockets that the IDF said had been smuggled into Gaza from Egypt.

The Fajr-5 rockets have a much wider range than other rockets of Hamas and can reach almost anywhere in Israel. It is those missiles that Israel has been targeting and hoping to destroy, according to the IDF.

Israel has also been attacking homes of Hamas leaders and terrorists, it said. In Gaza, some people were moving deeper into the territory to try and avoid Israeli airstrikes. Power outages were lasting 10 hours a day.

Panic spread through Gaza City on Tuesday evening after Israel Defense Forces dropped leaflets on the north of the city warning residents to evacuate.

"When we left our office we saw a lot of traffic and couldn't find a taxi to get home because people were busy evacuating their families using any transport possible," said Sukrit Kapoor, a lawyer with the Palestinian Center for Human Rights in Gaza City, which had evacuated its offices.

Thousands of Israeli troops and armored vehicles were massed along the Gaza border awaiting orders. Leaders of Hamas, the U.S. designated terrorist group the rules Gaza, exhorted its members to keep firing rockets.

Kapoor said some Gazans would rather see a cease-fire.

"They are very much hopeful for it, and very much want that to happen but right now it is difficult to be assured," he said. "A lot of people were displaced today so they are not very convinced that a cease-fire is close."

Others Gazans said they wanted to keep up the attacks against Israel even it meant more dead in Gaza, where Israeli airstrikes have targeted militants orchestrating the attacks.

Israeli strikes destroyed Abdullah Ashour's home, killed one of his sons and seriously injured another.

"The Israelis not capable of targeting the resistance, that's why they keep on targeting the normal civilians," said Ashour. "I'm willing to give up my other five sons for the sake of the cause."

In Ashkelon in southern Israel "Code Red" sirens sounded throughout Monday in cities, towns and open areas.

Even though the Iron Dome defense system intercepted most of the projectiles, there were several direct hits on buildings and yards. A handful of people were injured and many were dealing with shock from the constant blasts, said Benny Vaknin, mayor of Ashkelon.

The mayor spoke while looking over damage to Henry Ronson High School in Ashkelon, where a Hamas-fired rocket had scored a direct hit, bursting through the cement roof of a school walkway.The rocket did not explode and the school was empty at the time.

"The difference between our operation and that of Hamas is that they aim to hit schools and areas crowded with civilians," Vaknin said.

Alerts and air raid sirens were heard throughout the day in Israel's south from Beer Sheva and Sderot all the way up to Ashdod and beyond. There were two rocket interceptions near Tel Aviv.

Any cease-fire deal would draw mixed reviews from the Israeli towns and villages that have been the target of Hamas rockets.

Israelis are solidly behind the military action. Six days into the aerial attack on Gaza, 84% of the Israeli public said it supports so-called Operation Pillar of Defense, according to a Haaretz-Dialog poll taken Sunday.

Mervyn Poliak, a 64-year-old resident of Kfar Azza, said he's often felt helpless in the face of a decade of rocket fire and wants the army to invade and take care of Hamas once and for all.

"I've felt the government has left us to be sitting ducks here," he said. The international community "must let the Israeli government do its job.

"If Mexico or Canada was rocketing the US, the American government would have gone in long ago," he said. "When my enemy places its weapons next to a mosque or a school, how can they not expect people to get hurt?"

In Beer Sheva, most of the city's 200,000 residents took shelter in secure rooms, if they had them, or bomb shelters. Hundreds of regular soldiers and reservists waited at Beer Sheva's Central Bus Station for transport to the Gaza border some 25 miles away.

The mostly young men and women in uniform (women are also drafted in Israel) said they were trying to stay upbeat.

"I need to go and help my country any way I can," said Naftali Kassa, 27, a driver in civilian life. His rumpled uniform, taken out of storage, and gray sneakers identified him as a reservist.

Ehud Zion-Waldoks, a university spokesman who moved from Jerusalem to Be'er Sheva four months ago, decided to temporarily relocate his wife and three young children from harms ways. Zion Waldoks returned to Beer Sheva for work this morning, after which five sirens wailed.

"For one siren there were four booms, one of which shook the house," he said. "I feel safe in my house because we have an actual bomb shelter off the kitchen. I don't feel safe outside, going to and from work. My wife, who can't work on her doctorate due to the situation, and kids are now in Jerusalem."

He said his 5-year-old daughter was "a little upset" when a siren sounded in Jerusalem "after we'd told her the rockets couldn't reach there."

Right now he and his wife "take it day by day. We assess every evening what will be done. I don't' know whether this - either not being at home or being at home with five sirens a day - is possible long term."