LONDON, Dec 31 (AFP) - US President-elect George W Bush is set to begin withdrawal of US troops from the Balkans as soon as he arrives in the White House, with a complete withdrawal envisaged over four years, the Sunday Times newspaper reported.

"As soon as he (Bush) arrives, there will be a drawing down of American forces and after four years there will be no American ground troops in the Balkans," the paper quoted senior White House advisor John Hulsman as saying.

"There will be a philosophical sea change when Bush is in the White House," he added.

But another Bush advisor, Richard Perle, told the Sunday Times that the US would not act without consulting its allies. The United States currently has around 5,500 troops in the Kosovo and 4,500 in Bosnia, Perle said.

In an interview with the New York Times in October, Bush's designated national security advisor Condoleeza Rice caused concern amongst NATO members when she said that US would withdraw from the Balkans to leave Europe in full charge of maintaining peace in the region.

NATO Secretary General George Robertson moved to calm European nerves earlier this month when he said Rice's proposals had been misinterpreted.

"In my dealings with the Bush campaign team, I was assured that the United States would not make a unilateral decision without consulting its partners," Robertson said.

He added that during the presidential campaign, Bush had himself rejected rumblings heard in the US Senate that US troops would be  withdrawn from Kosovo next year.

NATO is in charge of the multilateral peacekeeping force in Kosovo (KFOR) and the stabilization force in Bosnia (SFOR).