"President Bush spoke this morning with President Kwasniewski and conveyed our strong support for European mediation in that phone call," US State Department spokesman Richard Boucher told a news briefing.

Polish President Kwasniewski arrived in Kiev Friday to help mediate in the crisis arising from Ukraine's disputed presidentialelection.

Secretary of State Colin Powell also talked to the European Union's top foreign policy official Javier Solana on the issue as well, Boucher said.

Prior to this, Powell had spoken with Ukrainian President Leonid Kuchma and Russian Foreign Minister Sergei Lavrov over the Ukraine's presidential election which is allegedly marred by fraud.

In addition, Boucher said, US Deputy Secretary of State RichardLee Armitage has phoned Ukraine's presidential candidates Viktor Yanukovych and Viktor Yushchenko to encourage them to look for peaceful democratic efforts to resolve all the questions related to the disputed election.

"The deputy secretary also conveyed to Prime Minister Yanukovych our strong objections to any separatist initiatives, and to urge the government and his supporters to refrain from any use of force," Boucher added.

Hundreds of thousands of people in Ukraine have been protesting against the results of the November 21 presidential vote, in which pro-Russia Prime Minister Yanukovich was named the winner over pro-Western opposition leader Yushchenko.