U.S. Secretary of State Hillary Clinton is back in Israel Wednesday after a visit to the West Bank where she continued her efforts to broker a truce between Israel and Gaza's militant Hamas rulers.

However, despite reports Tuesday that a cease-fire may be on the horizon, violence continued on both sides of the conflict. Israeli media reported Wednesday that an explosion on a bus across from the military headquarters in Tel Aviv injured at least 10, as Israeli airstrikes continued to pound Gaza overnight.

Clinton said the U.S. "strongly condemns" the bus bombing, calling it a "terrorist attack."

Zaki Heller from the Israeli rescue services told The Associated Press that the wounded in the bus explosion have varying degrees of injuries, but was unclear if anyone was killed. An Israeli driver who witnessed the explosion told Army Radio the bus was "completely charred inside."

Clinton went back to Jerusalem Wednesday after holding talks in the West Bank with Palestinian President Mahmoud Abbas.

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She will meet with Israeli Prime Minister Benjamin Netanyahu, Defense Minister Ehud Barak and Foreign Minister Avigdor Lieberman in her attempts to help piece together a deal that would satisfy the two foes after eight days of fighting.

Clinton, who will meet with Egyptian President Mohamed Morsi later Wednesday, has indicated it could take some time to iron out an agreement after more than a week of fighting.

"The goal must be a durable outcome that promotes regional stability and advances the security and legitimate aspirations of Israelis and Palestinians alike," Clinton said after meeting with Netanyahu.

The two sides had seemed on the brink of a deal following a swirl of diplomatic activity also involving the U.N. chief and Morsi. But sticking points could not be resolved as talks -- and violence -- stretched into the night.

Meanwhile, Israeli aircraft pounded Gaza with at least 30 strikes overnight Tuesday, 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.

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.

Medics said a child living in the area 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.

In the West Bank, Clinton was to meet with Palestinian President Mahmoud Abbas. 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.

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.

Hamas official Izzat Risheq predicted a truce deal would be reached Wednesday, but the movement wouldn't discuss what the problems were.

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 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.

Israel 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.

The Associated Press and Reuters contributed to this report.