There is credible information that Nairobi hotels and prominent government buildings could be hit, according to a statement by the embassy.
"Timing of the attack is not known, however, the Embassy has reason to believe that the potential attack is in the last stages of planning," the statement
says. "The U.S. Embassy urges Americans to remain aware of their surroundings and vigilant of their personal security."
The Kenyan government did not come with an immediate comment, according to the VOA
which reported there have been a number of small-scale attacks in Nairobi and in northeastern Kenya after government sent troops into Somalia to fight the militant group al-Shabab last October.
In August 1998, over 200 people died after militants linked to al-Qaida bombed the U.S. embassy in Nairobi.