At least one person was killed and 14 others were wounded in explosions in a restaurant in the Kenyan city of Mombasa and in the nearby town of Mtwapa, police said.
In Mtwapa "what appears to be a grenade" was thrown at a Christian religious gathering injuring 12 people", Coast police chief Aggrey Adoli told AFP.
A second police source, who asked not to be named, said one of the 12 died from his injuries on his way to or on arrival at hospital.
Adoli said that a second grenade was "hurled at a restaurant in Mombasa" and that three people, including one police officer, sustained minor injuries.
He had earlier said no one was injured in the Mombasa attack, which local people said targeted a restaurant next door to the football stadium popular with non-Muslims and renowned for serving pork delicacies.
Adoli said the first blast in Mtwapa occurred after 8:00 pm (1700 GMT) and the second within minutes of it.
Since Kenya sent tanks and troops into Somalia late last year, several grenade attacks and explosions have taken place, both in Nairobi and in eastern towns close to the Somali border.
Targets have ranged from police vehicles to bars.
Saturday's blasts were the first reported in the coastal areas, which are among Kenya's great tourist magnets.
Mombasa's resort hotels line the coast, away from the town centre.