The quartet of four powers behind the stalled Middle East peace plan - the roadmap - have outlined measures to encourage a resumption of peace talks.
Hopes for peace in the Middle East have receded
After meeting in New York, they reaffirmed their commitment to a negotiated two-state solution - but warned against unilateral actions.
Israeli Prime Minister Ariel Sharon has seen his plan to fully withdraw from Gaza rejected by his own party, Likud.
But the quartet said Mr Sharon's plan must provide a "rare moment" for peace.
The quartet is made up of the United States, Russia, the European Union and the United Nations.
Earlier, a number of retired US diplomats wrote to complain to President George W Bush about his Middle East policy.
They criticised his "unabashed support" for Mr Sharon.
Mr Bush sparked controversy by endorsing Mr Sharon's plan to pull out of Israeli settlements in Gaza - while retaining many in the West Bank.
This meant the roadmap, in reality, had no future, says the BBC News Online's world affairs correspondent, Paul Reynolds.
US Secretary of State Colin Powell said the latest statement should placate Arab governments who complain that Mr Bush has given in to Israel.
"I think that the statement we have made today on behalf of the quartet... is some assurance to the Arab world and to the whole world that we are committed to the basis upon which the peace process rests," Mr Powell said.
UN Secretary General Kofi Annan hosted Tuesday's meeting, in which Russian Foreign Minister Sergei Lavrov and EU foreign policy chief Javier Solana attended, among others.
Mr Annan called on the Palestinian Authority to act against militants, and urged Israel to do its best to avoid civilian casualties.
The quartet called for "renewed efforts to reach a comprehensive ceasefire as a step towards dismantlement of terrorist capabilities and infrastructure".
They said an oversight committee, led by the US, would be established to make sure Palestinian security forces were restructured and retrained, consistent with the roadmap.
In the first Palestinian reaction, Foreign Minister Nabil Shaath called for a fresh "action plan" for ending the conflict.
"We need an action plan that gets us to peace and to stop all the violence, end occupation and bring us back into negotiations," Mr Shaath said in London, after talks with UK Foreign Secretary Jack Straw.
Sharon plan welcomed
In New York, the four powers "took positive note of the announced intention of Israeli Prime Minister Sharon to withdraw from all Gaza settlements and parts of the West Bank".
"The quartet welcomes and encourages such a step, which should provide a rare moment of opportunity in the search for peace in the Middle East," the statement said.
ROADMAP: MAIN STAGES
Phase 1 (originally intended to take place by May 2003): End to violence against Israelis and Palestinians; Palestinian political reform; Israeli withdrawal and freeze on settlement expansion; Palestinian elections
Phase 2: (June-Dec 2003) Creation of an independent Palestinian state; international conference and international monitoring of compliance with roadmap
Phase 3 (2004-2005): Second international conference; permanent status agreement and end of conflict; agreement on final borders, Jerusalem, refugees and settlements; Arab states to agree to peace deals with Israel
"This initiative, which must bring about a full Israeli withdrawal and complete end of occupation in Gaza, can be a step towards achieving the two-state vision; and has the possibility of restarting progress on the roadmap."
Mr Sharon's disengagement plan was rejected by his own Likud party members on Sunday, but it is thought to have wide support from ordinary Israelis.
He is consulting coalition members - and the opposition - with a view to amending the plan.
Reports suggested he could propose to pull out of only three - out of all the 21 - Gaza Strip settlements, and two - not four - West Bank ones.
But Labour Party Shimon Peres told Mr Sharon he will support only the full disengagement plan and not a limited version of it.