US President Mr George W. Bush told Israeli Prime Minister Mr Ariel Sharon today he condemned a new outbreak of suicide bombings in Israel.
President Bush also demanded Palestinian leader Mr Yasser Arafat act decisively against militant groups.
In a grim meeting on a day that new bombings brought the toll in a weekend of death to at least 25, Mr Bush and Mr Sharon talked for more than an hour in the Oval Office.
The Israeli leader left the White House without commenting this evening. He was due to rush home immediately as the specter of Israeli retaliation loomed.
The United States clearly put the onus on Mr Arafat to take action to rein in Palestinian militants.
"Mr Bush said he wanted Chairman Arafat and the Palestinian Authority to ensure the immediate arrests of those responsible for these heinous acts and decisive action against the organisations like Hamas and Palestinian Islamic Jihad that support them," US National Security Council spokesman Mr Sean McCormack said.
Before meeting Mr Sharon in Washington, a Mr Bush said it was time for advocates of peace to rise up and fight terror.
In what Mr Sharon could interpret as an opening to pursue Israeli military retaliation, US Secretary of State Mr Colin Powell said today Mr Bush would leave it up to the Israeli leader to decide how to respond.
Asked whether Mr Bush had asked Mr Sharon to show restraint, Mr McCormack referred to Mr Powell's remarks and declined to elaborate.
The violence was seen as a direct challenge to efforts by the new US Middle East envoy, retired Marine Gen Anthony Zinni, to end 14 months of Israeli-Palestinian violence that has killed more than 900 people.