Nairobi, Kenya (CNN) -- A grenade attack targeting a church in the Kenyan capital left one person dead and 16 others injured Sunday, authorities said.
The gunman fled after throwing the grenade into the church in Nairobi's Ngara area, said Eric Kiraithe, a police spokesman. The pastor was among the wounded.
There was no immediate claim of responsibility for the attack, which occurred in a peaceful area of the capital.
Kenya has been hit by a series of grenade attacks -- including two on the coast this month that killed one and injured 33 -- since it sent troops to Somalia in October.
The troops are battling the Islamic extremist group Al-Shabaab, which Kenya accuses of targeting tourist resorts and kidnapping foreigners in the nation.
Al-Shabaab vowed to revenge, saying it considers the incursion an affront to Somalia's sovereignty.
The latest attack comes on the heels of U.S. Embassy warnings last week that terrorists may be planning strikes against hotels and government buildings in Kenya.
The embassy said it had credible information that the attacks are in the final planning stage, but said the timing is not known.
Officials in Britain and the United States have repeatedly warned in recent months of expected attacks in Kenya, which suffered from a spate of abductions of aid workers and tourists late last year.
CNN's Samira Said contributed to the report.