(CBS/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 attack came as diplomats, including U.S. Secretary of State Hillary Rodham Clinton, shuttled around the region to try to broker a cease-fire following a week-long Israeli offensive against Palestinian militants in Gaza that intensified to its most feverish state yet overnight, according to CBS News correspondent Charlie D'Agata. Palestinian officials say more than 140 people have been killed, and 1,000 wounded -- most of them civilians, and many children among them.
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.
This, as thousands of Israeli ground troops massed on the Gaza border awaiting a possible order to invade.
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 Israel's national defense headquarters.
The bus was charred and blackened, its side windows blown out and its glass scattered on the asphalt. The wounded were evacuated and blood was splattered on the sidewalk.
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. The witnesses spoke to Israeli TV and were not identified.
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.
"We strongly believe that this was a terror attack," he said.
He said that of the 10 wounded, three were moderately to seriously hurt.
The last bombing in Tel Aviv was in April 2006, when a Palestinian suicide bomber killed 11 people at a sandwich stand near the city's old central bus station. A bomb left at a bus stand in Jerusalem last year killed one person.
There was no claim of responsibility from Hamas or the Islamic Jihad.
Clinton meets with Mideast leaders.Clinton pressed on Wednesday with efforts to wring an elusive truce deal from Israel and Gaza's militant Hamas rulers, after earlier attempts to end more than a week of fighting broke down amid a furious spasm of violence.
She joined other world diplomats in shuttling between Jerusalem, the West Bank and Cairo, trying to piece together a deal that would satisfy the two foes after a week of fighting and mounting casualties.
After meeting with Israeli Prime Minister Benjamin Netanyahu in Jerusalem Tuesday night, Clinton conferred with Palestinian President Mahmoud Abbas in the West Bank on Wednesday morning, then arrived in Cairo, where the new Muslim Brotherhood-led government is mediating in the crisis.
CBS News correspondent Margaret Brennen reports that Clinton was to meet Wednesday in Cairo with Egyptian President Mohammed Morsi, Foreign Minister Mohamed Kamel Amr, and Arab League Secretary-General Nabil al Araby.
The two sides had seemed on the brink of a deal Tuesday following a swirl of diplomatic activity also involving the U.N. chief and Egypt's president. But sticking points could not be resolved as talks -- and violence -- stretched into the night.
At least four strikes within seconds of each other pulverized a complex of government ministries the size of a city block, rattling nearby buildings and shattering surrounding windows. Hours later, clouds of acrid dust still hung over the area and smoke still rose from the rubble.
The impact of the blast demolished the nearby office of attorney Salem Dahdouh, who was searching through files buried in the debris.
"Where are human rights?" he asked, saying officials negotiating a cease-fire ought to see the devastation.
In downtown Gaza City, another strike leveled the empty, two-story home of a well-known banker and buried a police car parked nearby in rubble.
"This is an injustice carried out by the Israelis," said the house's caretaker, Mohammed Samara. "There were no resistance fighters here. We want to live in peace. Our children want to live in peace. We want to live like people in the rest of the world."
Medics said an area child was killed, raising the Palestinian death toll to at least 138. Five Israelis have also been killed by Palestinian rocket fire, which continued early Wednesday.
The Israeli military said its targets included the Ministry of Internal Security, which it says served as one of Hamas' main command and control centers, a military hideout used as a senior operatives' meeting place and a communications center.
Washington blames Hamas rocket fire for the outbreak of violence and has backed Israel's right to defend itself, but has cautioned that an Israeli ground invasion could send casualties soaring.
"In the days ahead, the United States will work with our partners here in Israel and across the region toward an outcome that bolsters security for the people of Israel, improves conditions for the people of Gaza and moves toward a comprehensive peace for all people of the region," she said Tuesday night in Jerusalem, speaking alongside Netanyahu.
While Abbas does not have any practical influence in Gaza, his West Bank government would be instrumental in implementing any new arrangements on the Gaza border that would be part of a cease-fire pact. Israel and Egypt slammed shut the border after the militant group seized the territory from Abbas in June 2007, hoping to disrupt Hamas rule. Both sides have since eased the restrictions, but many remain.
The U.S. considers Hamas, which has killed hundreds of Israelis in suicide and other attacks, to be a terror group and does not meet with its officials.
Israeli media quoted Defense Minister Ehud Barak as telling a closed meeting that Israel wanted a 24-hour test period of no rocket fire to see if Hamas could enforce a truce among its forces and other Gaza militant groups.
Palestinian officials briefed on the negotiations said Hamas wanted assurances of a comprehensive deal that included new arrangements for prying open Gaza's heavily restricted borders, and were resisting Israeli proposals for a phased agreement. The officials spoke on condition of anonymity because they were not authorized to talk to the media.
Israel's outspoken foreign minister, meanwhile, expressed what many in Israel suspect -- that ahead of January elections, the country's leaders do not want to get mired in a ground operation.
"There is no point embarking on such a dramatic move two months before elections after we didn't do it for four years," Foreign Minister Avigdor Lieberman told the Ynet web site Tuesday. Israeli government spokesman Mark Regev had no comment on Lieberman's remarks.
Israel launched the offensive on Nov. 14 following months of rocket salvoes from the territory into southern Israel, which has endured attacks for the past 13 years. For its opening salvo, it assassinated Hamas' military chief, then followed up by bombarding the militant-run territory to its south with more than 1,500 airstrikes that initially targeted rocket launchers and weapons storage sites, then widened to include wanted militants and symbols of Hamas power.
Defying Israel's claims that they've been badly battered, the militants have so far fired more than 1,400 rockets at Israel, drawing upon newly developed and smuggled weapons to extend the reach of their attacks toward Tel Aviv and Jerusalem, Israel's largest cities. The number of Israelis within rocket range leapt to 3.5 million from 1 million.
Dozens of civilians are among the more than 130 Palestinians killed in a week of fighting. Four Israeli civilians and a soldier have been killed by rocket fire, a toll possibly kept down by a U.S.-funded rocket defense system that has shot down hundreds of Gaza projectiles.
In a meeting with Netanyahu, U.N. chief Ban Ki-moon condemned Palestinian rocket attacks, but urged Israel to show "maximum restraint."
"Further escalation benefits no one," he said before returning to Egypt, which is mediating the truce talks.
srael demands an end to rocket fire from Gaza and a halt to weapons smuggling into the territory through tunnels under the border with Egypt. It also wants international guarantees that Hamas will not rearm or use Egypt's Sinai region, which abuts both Gaza and southern Israel, to attack Israelis.
Hamas wants Israel to halt all attacks on Gaza and lift tight restrictions on trade and movement in and out of the territory that have been in place since it seized the territory. Israel has rejected such demands in the past.
Egypt's new Islamist government is playing a key role in the negotiations to broker a deal between the two sides, which shun each other. It is also expected to play a pivotal role in maintaining any deal, performing a difficult balancing act as an ideological ally of Hamas, recipient of U.S. aid and one of just two of Israel's Arab neighbors to have made peace with Israel.