Israeli Prime Minister Mr Ariel Sharon has demanded 10 days of total calm with the Palestinians before proceeding with a US plan to end nine months of bloodshed.
"I said it very clearly. Israel will never negotiate under fire," Mr Sharon said after talks with US President Mr George W. Bush at the White House. Shortly afterwards, Secretary of State Mr Colin Powell left for the Middle East to bolster the shaky two-week-old ceasefire.
But Mr Sharon cast doubt on Mr Powell's chances of success.
"I don't know if he will succeed in achieving a result because [Palestinian leader Yasser] Arafat has simply decided to continue terror. That's the problem. And if massive pressure is not brought upon him, he won't stop it," Mr Sharon said.
The cooling-off period, which Mr Sharon said should last at least six weeks, is part of a peace blueprint drawn by an international committee led by former US senator Mr George Mitchell.
President Bush said the cycle of violence must be broken and that there was some progress in reducing clashes between Israelis and Palestinians.
"Is peace closer today than it was yesterday? We believe the answer is 'yes'. Progress is being made," he said.
Mr Sharon said there was not a deterioration in US-Israeli relations - describing his meeting with Mr Bush as an exciting and special meeting.