Saudi Arabia has threatened to prop up embattled Egyptian President Hosni Mubarak if the Obama administration tries to force a swift change of regime in Egypt, The Times of London reported Thursday.

In a testy personal telephone call on Jan. 29, Saudi Arabia's King Abdullah reportedly told President Obama not to humiliate Mubarak and warned that he would step in to bankroll Egypt if the U.S. withdrew its aid program, worth $1.5 billion annually.

America's closest ally in the Gulf made clear that the Egyptian president must be allowed to stay on to oversee the transition towards peaceful democracy and then leave with dignity.

"Mubarak and King Abdullah are not just allies, they are close friends, and the King is not about to see his friend cast aside and humiliated," a senior source in the Saudi capital told The Times.