Security experts in Britain and the United States say President-elect Barack Obama must be aware of a looming terror threat from al-Qaida militants.

CIA Director Michael Hayden and British Home Office Security Minister Alan West each have warned of potential al-Qaida attacks, possibly during the transition period between U.S. presidents, The Times of London reported Saturday.

"If there is a major attack on this country it will bear the fingerprints of al-Qaida," Hayden said at a think-tank meeting Thursday in Washington.

"Al-Qaida, operating from its safe haven in Pakistan's tribal areas, remains the most clear and present danger to the safety of the United States."

The Times said British security officials such as West are particularly concerned the presidential transition period in the United States.

"There is another great plot building up again and we are monitoring this," West said.