Kenyan police say a grenade attack at a Nairobi church Sunday killed one person and wounded at least 10 others, some seriously.

There has been no immediate claim of responsibility for the attack at Gods House of Miracle International Church in Kenya's capital. Police are investigating who is responsible.

Sunday's attack comes six days after a warning from the U.S. embassy in Kenya of possible terrorist attacks in Nairobi. The embassy issued a message last Monday telling Americans to stay alert.

The embassy said it had credible information about a possible attack on Nairobi hotels and prominent Kenyan government buildings. The statement said the timing of the attack was not known, but that the embassy had “reason to believe the potential attack” was in the last stages of planning.