Washington - The United States has played down the possibility that the increased political turmoil surrounding Israeli Prime Minister Ehud Olmert will disrupt the peace process with the Palestinians.

"I defy anyone to tell me a moment when there was not some kind of internal political turmoil, either in the Palestinian community or in the Israeli political process," US State Department deputy spokesman Tom Casey said Wednesday.

"If you want to wait for a perfect moment to begin discussions or to continue the discussions or further them along, you'll be waiting an awfully long time," Casey added.

The pressure on Olmert to resign increased on Wednesday, one day after a US businessman, Morris Talansky, testified that he provided the prime minister with 150,000 dollars in cash during a 15-year- period prior to Olmert's current job.

Defence Minister Ehud Barak, a former prime minister and leader of Olmert's largest coalition partner, on Wednesday called on Olmert to relinquish power, questioning his ability to run the country and head peace negotiations.

Olmert has refused to resign, saying the money was used to fund campaigns when he was running for mayor and when he was a member of the Likud party. Olmert now leads the Kadima party and governs in a coalition with Barak's Labour Party.

Olmert has said he will leave office if he's indicted in the scandal probing his finances.

The spokesman for Palestinian President Mahmoud Abbas, Nabil Abu Rudeineh, said there was "no doubt" Olmert's problems will negatively affect the peace process. But the United States believes negotiations can move forward.

"Our goal here is not to achieve an agreement based on the personalities of President Abbas and Prime Minister Olmert," Casey said. "Our goal here is to achieve an agreement that serves the interests of the Palestinian people and of the Israeli people."

President George W Bush in November secured an agreement between Olmert and Abbas to resume negotations with the goal of reaching a deal by the end of 2008. (dpa)