contagiousness carry: Blast hits bus in Tel Aviv as Gaza crisis rages

A bus in Tel Aviv exploded this morning injuring at least ten according to police sources. MSNBC's Mika Brzezinski reports.

By NBC News staff and wire reports

Updated at 8:04 a.m. ET:?An explosion on a bus in Tel Aviv on Wednesday injured 10 people, three of them seriously, a medical official told NBC News as the deadly Gaza crisis continued.

The blast happened as Israeli airstrikes continued to shake the Gaza Strip and Palestinian rockets were fired into Israel, amid negotiations about?a possible truce.

Tel Aviv police spokesman Micky Rosenfeld told the U.K.'s Sky News that the bus blast took place in the heart of the city and that the surrounding area had been cordoned off as police searched for suspects.

"At the moment, we're looking to see exactly what was the cause of the explosion itself," Rosenfeld said, adding it might have been caused by a device left on the bus or taken on by a passenger.

"This was a terrorist attack," Ofir Gendelman, a spokesman for Israeli Prime Minister Benjamin Netanyahu, told Reuters.

The White House condemned the attack as "outrageous."?In a statement, it reaffirmed the United States' "unshakeable commitment to Israel's security and our deep friendship and solidarity with the Israeli people."

Secretary of State Hillary Clinton arrived in Cairo on Wednesday, where she?was due to meet Egyptian President Mohammed Morsi. Speaking earlier in Jerusalem, she?Netanyahu of "rock-solid" U.S. support for Israel's security and spoke of seeking a "durable outcome" and of Egypt's "responsibility" for promoting peace.

Avital Leibovich, an Israel Defense Forces spokesperson,?said on Twitter?that the blast happened near her office in Tel Aviv. "Still looking for the bomber, more police sirens, helicopter still in the air," she tweeted at about 5:43 a.m. ET.

'Hamas blesses the attack'
Hamas spokesman Sami Abu Zuhri praised the bombing, but stopped short of claiming responsibility.

Nir Elias / Reuters

Israeli police survey the scene after an explosion on a bus in Tel Aviv Wednesday.

"Hamas blesses the attack in Tel Aviv and sees it as a natural response to the Israeli massacres...in Gaza," he told Reuters. "Palestinian factions will resort to all means in order to protect our Palestinian civilians in the absence of a world effort to stop the Israeli aggression."

More photos: Explosion hits bus in Tel Aviv

Sweet cakes were handed out in celebration in Gaza's main hospital, which has been inundated with wounded from the round-the-clock Israeli bombing and shelling, Reuters reported.?Celebratory gunfire also rang out in Gaza City when local radio stations reported the news.

Yonatan Yagodovsky, a spokesman for the Magen David Adom emergency medical service, told NBC News that 10 people were being treated for wounds caused by the blast.

Three sustained moderate to serious injuries and the condition of "at least one" patient was life-threatening, he said.?The other seven had light to moderate injuries, Yagodovsky said, adding that six or seven people were also treated for "stress" caused by the explosion.?

The last time Israel's commercial capital was hit by a serious bomb blast was in April 2006, when a Palestinian suicide bomber killed 11 people at a sandwich stand near the city's old central bus station.

Oliver Weiken / EPA

A Palestinian looks at government offices destroyed in an Israeli airstrike in Gaza City on Wednesday.

Egypt's new Islamist government, which is mediating talks, had floated hopes for a cease-fire by late Tuesday between Israel and Hamas, the Islamist movement controlling Gaza.

But as Clinton arrived in Israel after nightfall Tuesday, Israel stepped up its bombardment from air and sea. At one point, munitions slammed into Gaza at a rate of one every 10 minutes, Reuters said.

Gazan rocket fire waned overnight but resumed before dawn on Wednesday. Israel said early Wednesday that 30 rockets had been fired since midnight.?Ashkelon and Saar Hanegev were reportedly hit, but there no reports of damage or injuries.

Medical officials in Gaza said 31 Palestinians were killed on Tuesday. An Israeli soldier and a civilian died when rockets exploded near the Gaza frontier, police and the army said.

So far a total of more than 130 Palestinians and five Israelis have been killed in a week of conflict, according to Reuters and The Associated Press.

Secretary of State Hillary Clinton has undertaken the difficult task of helping to shepherd a possible ceasefire. Egyptian president Mohammed Morsi, meanwhile, is playing a key role as an intermediary with Hamas, a group labeled by the U.S. as a terrorist organization. NBC's Stephanie Gosk reports.

Analysis: Why Hezbollah is sitting out the Gaza conflict

The Israel Defense Forces website said Wednesday that the IDF had targeted more than 100 "terrorist sites" overnight, including Hamas' Ministry of Internal Security, a police compound and a "military hideout" used by "senior operatives."

In downtown Gaza City, a 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," the house's caretaker, Mohammed Samara told The Associated Press. "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."

A flurry of violence hit Gaza Tuesday as Israel bombed a Gaza bank and targeted the homes of militants. Hamas responded with more than 100 rockets. NBC's Richard Engel reports.

'We are very scared': Egyptians fear being mired in Gaza-Israel crisis

An article posted on the IDF website Wednesday said that Hamas and "Gaza's other terror groups" had fired more than 12,000 rockets at Israel over the past 12 years and had "deliberately targeted civilians."

It added that "many residents of southern Israel today suffer from post-traumatic stress disorder."

The IDF posted a video in which Israelis described what it was like living under the threat of rocket fire from Gaza:

'Army must invade': In southern Israel, support grows for action in Gaza

Israel Radio quoted an Israeli official saying a truce was held up due to "a last-minute delay in the understandings between Hamas and Israel."

Hamas leaders in Cairo accused the Jewish state of failing to respond to proposals and said an announcement on holding fire would not come before daylight on Wednesday.

Secretary of State Hillary Clinton is attempting to bring about a ceasefire, or to prevent Israel from invading Gaza while convincing Egypt's president to pressure Hamas to stop firing rockets. NBC's Andrea Mitchell reports.

Like most Western powers, Washington shuns Hamas as an obstacle to peace and has blamed it for the Gaza conflagration.

Americans caught in chaos of Gaza conflict

A U.N. Security Council statement condemning the conflict was blocked on Tuesday by the United States, which complained that it "failed to address the root cause" -- the Palestinian rockets.

NBC's Lawahez Jabari and Ian Johnston, Reuters and The Associated Press contributed to this report.