The United States, Russia, European Union and United Nations on Monday called on the Palestinians and Israelis to halt "provocative actions" in a bid to end renewed clashes between the two.
Top officials from the so-called diplomatic Quartet on the Middle East -- including US Secretary of State Hillary Clinton and Russian Foreign Minister Sergei Lavrov -- met as Israel staged new air strikes on Gaza in response to scores of rockets fired into the Jewish state.
The four "discussed the grave situation in Gaza and southern Israel, expressed serious concern for the recent escalation and called for calm," said a statement released after the meeting.
"The Quartet reiterates its call on the parties to remain engaged and to refrain from provocative actions."
Clinton, Lavrov, UN Secretary General Ban Ki-moon and Quartet envoy Tony Blair met at the UN headquarters. EU foreign affairs representative Catherine Ashton took part in the talks by video-conference.
Israeli warplanes pounded the Gaza Strip for a fourth day as the talks were held. Twenty-three Palestinians are now reported dead. Israel says it is hitting back at scores of rocket attacks from Gaza.
At a UN Security Council meeting on the Middle East, US Secretary of State Hillary Clinton condemned "in the strongest terms" the rocket fire from the Gaza Strip.
"We call on those responsible to take immediate action to stop these attacks," she said.
"And we call on both sides, all sides, to make every effort to restore calm," Clinton added.
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The Quartet has been trying to find a negotiated way to set up a Palestinian state. But its efforts have become deadlocked as there have been no direct Palestinian-Israeli peace talks since September 2010.
The four launched a new bid to bring the two sides back to the negotiating table on September 23 last year, when the Palestinians made their application for full membership of the UN.
The Palestinians say there can be no talks while Israel continues its expansion of settlement building in the occupied territories.
The diplomatic quagmire has been deepened by the Palestinian attempts to seek greater international recognition, in frustration at the deadlock in the talks. The United States has vowed to veto any Security Council resolution in favor of the Palestinians.
The US administration and Israel say that only direct talks can create a deal to set up a Palestinian state.
Several ministers called for action on the Palestinian-Israel crisis.
"Are the claims of the Palestinians (for a state) not just as legitimate as those expressed in the rest of the region?" French Foreign Minister Alain Juppe, who reaffirmed France's support for Israel's security, told the Security Council meeting.
Russia's foreign minister told the same meeting the Arab Spring should not "weaken attention" on the Middle East conflict.
"We are convinced that the conflict potential in the Middle East and Northern Africa will remain high until a comprehensive settlement is achieved in the Middle East within the existing international legal framework," Lavrov said.
The Quartet decided to meet again in Washington in April.