Although it has no evidence of a specific plot, the FBI has warned that it possesses intelligence that terrorists are interested in using shoe bombs to down airliners -- like the attack foiled a year ago.

In its latest intelligence bulletin, the FBI urged law enforcement nationwide to stay vigilant to the possibility that terrorists might try to hide bombs in bulky winter coats, shoes or other garments.

"The U.S. intelligence community continues to receive credible information that terrorist operatives remain interested in utilizing shoe bombs during the conduct of hijackings or other attacks against commercial airliners," said the bulletin sent Monday night.

Meanwhile, the State Department alerted Americans in East Africa yesterday that terrorists might strike and said Kenya's capital, Nairobi, was under threat of missile attack.

Similar attacks may occur in the East African nation Djibouti, the department said, citing unconfirmed information.

In Nairobi, there is an increased threat against Westerners. The department advised U.S. citizens there and those planning to travel to Kenya to be wary.

A car bomb at an Israeli-owned hotel near Mombasa, Kenya, last month killed 12 people.

That attack, along with an attempt to shoot down an Israeli charter plane, highlight the continuing threat posed by terrorism in the region, the department said.