GAZA (Reuters) - Israeli warplanes pounded the Hamas-ruled Gaza Strip on Saturday, killing at least 229 people in one of the bloodiest days for the Palestinians in 60 years of conflict with the Jewish state.

Hamas vowed revenge including suicide bomb attacks in the “cafes and streets” of Israel, as Israeli air strikes continued late into the night. Israel said the offensive would continue as long as necessary and that it may also involve land forces.

Israel said the strikes were in response to almost daily “intolerable” rocket and mortar fire by Gaza militants, which intensified after Hamas ended a six-month ceasefire a week ago.

The rockets caused few injuries, but Israeli leaders were under pressure to stop these attacks ahead of a February 10 election which opinion polls show the right-wing opposition Likud party may win. On Saturday, one Israeli man was killed by a rocket fired after the Israeli strikes began.

“There is a time for calm and a time for fighting, and now the time has come to fight,” Israeli Defense Minister Ehud Barak said in a televised statement. He later ruled out any new truce with Hamas.

Outgoing Prime Minister Ehud Olmert warned that “it may take time, and each and every one of us must be patient so we can complete the mission.”

Israel Radio said Israeli infantry and armored forces had been reinforced along the border with Gaza after the attacks.

Hamas leader Ismail Haniyeh said “Palestine has never seen an uglier massacre” and in Damascus, Hamas leader Khaled Meshaal called for a new Palestinian peoples’ uprising against Israel.

“We will not leave our land, we will not raise white flags and we will not kneel except before God,” Haniyeh said.

Black smoke billowed over Gaza City, where the dead and wounded lay on the ground after Israel bombed more than 40 security compounds, including two where Hamas was hosting graduation ceremonies for new recruits.

MORE THAN 700 WOUNDED

At the main Gaza City graduation ceremony, uniformed bodies lay in a pile and the wounded writhed in pain. Some rescue workers beat their heads and shouted “God is greatest.” One badly wounded man quietly recited verses from the Koran.

More than 700 Palestinians were wounded in all, medics said.

Israel said the operation, dubbed “Solid Lead,” targeted “terrorist infrastructure” following days of rocket attacks on southern Israel that caused damage but few injuries. Israeli army officials said Hamas leaders could be targeted.

A series of air strikes were launched after darkness fell. Israel telephoned some Palestinians to warn them their homes were targeted and they should leave to avoid being killed. In at least one instance a home was bombed after the occupants left.

Two Palestinians were killed when a mosque was bombed in Gaza City, Hamas officials and medics said.

Foreign Minister Tzipi Livni, a leading candidate to become Israel’s next prime minister, called for international support against “an extremist Islamist organization ... that is being supported by Iran,” Israel’s arch-foe.

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Israel instructed hundreds of thousands of Israelis living up to 30 km (19 miles) from the Gaza border to remain in “safe areas” indoors in case of retaliatory rocket fire.

Backing Israel, the administration of President George W. Bush, in its final weeks in office, put the onus on Hamas to prevent a further escalation.

“The United States ... holds Hamas responsible for breaking the ceasefire and for the renewal of violence in Gaza,” Secretary of State Condoleezza Rice said in a statement. “The ceasefire should be restored immediately.”

The United Nations and the European Union, in contrast, simply called for an immediate halt to all violence.

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Palestinian President Mahmoud Abbas said the Israeli air campaign was “criminal” and urged world powers to intervene.

Egypt said it would keep trying to restore the truce.

UPRISING CALL

Saturday’s death toll was the highest for a single day in the Israeli-Palestinian conflict since 1948, when the Jewish state was established.

“I call upon you to carry out a third intifada (uprising),” Hamas leader Meshaal said on Al-Jazeera television. The first Palestinian intifada began in 1987 and the second in 2000 after peace talks failed.

Hamas estimated that at least 100 members of its security forces had been killed, including police chief Tawfiq Jabber and the head of Hamas’s security and protection unit, along with at least 15 women and some children.

The Islamist group, which won a 2006 parliamentary election but was shunned by Western powers over its refusal to renounce violence and recognize Israel, said all of its security compounds in the Gaza Strip were destroyed or seriously damaged.

Aid groups said they feared the Israeli operation could fuel a humanitarian crisis in the impoverished coastal enclave, home to 1.5 million Palestinians, half of them dependent on food aid.

Gaza hospitals said they were running out of medical supplies because of the Israeli-led blockade. Israel said it would let 10 trucks into Gaza with vital medical supplies and flour on Sunday, a Palestinian official said.

Israeli analyst Ron Ben-Yishai said the strike was “shock treatment ... aimed at securing a long-term ceasefire between Hamas and Israel on terms that are favorable to Israel.”