Attackers have shot two people dead and wounded 10 when they burst into a church service near the Kenyan port city of Mombasa, spraying the congregation with bullets, police said.
Local police chief Robert Mureithi said the gunmen had killed the two worshippers, a man and a woman, and then fled.
The attack comes amid heightened warnings of a threat of Islamist attacks.
"Two people have been killed, they were shot by gunmen who shot indiscriminately at worshippers and then fled," said Mureithi, from the Likoni district just south of Mombasa.
"About 10 others were injured and they have been taken to hospital," he added, without giving details on how seriously they were wounded.
Kenya's National Disaster Operation Centre said there had been "mass casualties" in the attack, on the evangelical New Testament Church.
There was no immediate claim of responsibility but Kenya has been hit by a series of attacks since sending troops into southern Somalia in October 2011 to battle the Al-Qaeda-linked Shebab insurgents.
Kenyan troops, who have since joined the African Union force in Somalia, are taking part in a fresh offensive against Shebab bases launched this month.
