The U.S. embassy in Kenya is warning of possible terrorist attacks in the capital, Nairobi, and is telling Americans in the city to stay alert.

The embassy issued a message Monday saying it has credible information about a possible attack on Nairobi hotels and prominent Kenyan government buildings.

The statement says the timing of the attack is not known but that the embassy has “reason to believe the potential attack is in the last stages of planning.”

There was no immediate comment from the Kenyan government.

Britain issued a similar warning about possible attacks in January.

There have been a number of small-scale attacks in Nairobi and in northeastern Kenya since last October, when Kenya sent troops into Somalia to fight the militant group al-Shabab.

Militants linked to al-Qaida and Osama bin Laden bombed the U.S. embassy in Nairobi in August 1998, killing more than 200 people.