At least 45 people were wounded in the simultaneous attacks on Garissa, in the north of the East African country which has suffered a series of blasts since sending troops into Somalia last October to crush Somalia’s al Shabaab militants.
“We have 17 bodies at the mortuary so far,” regional medical officer Abdikadir Sheikh told Reuters.
There was no immediate claim of responsibility.
Police said they suspected the attacks could have been the work of al Shabaab sympathisers or bandits, but it was too early to say. Inside Somalia, al Shabaab declined comment.
“The goons were clad in balaclavas,” said regional deputy police chief Philip Ndolo from Garissa.
He said a total of seven attackers hurled grenades inside the Catholic Church and the African Inland Church and then opened fire with guns. They struck the churches, which are 3 kms apart, at around 10.15am (0715 GMT)
Two policemen were among the dead.
They were the latest attacks on Christian worshippers in Kenya after two people were killed in grenade blasts in March and April.
But yesterday’s coordinated attacks on churches resembled the tactics of Nigeria’s Islamist militant group Boko Haram, which has killed hundreds of people on the other side of the continent.
Other blasts in Kenya have hit nightclubs and bus stations in the capital Nairobi, the coastal city of Mombasa and areas near the Somalia border.
Although a majority of Kenyans are Christian, Garissa is more heavily Muslim.
The town of around 150,000, a market centre for the trade in camels, donkeys, goats and cattle, is largely populated by ethnic Somalis.
“You can imagine for such a small town how the police and medical services have been stretched trying to deal with this,” the police’s Ndolo said.
Garissa is about 100 kms from Kenya’s Dadaab refugee camp, where gunmen kidnapped four aid workers and killed a driver on Friday before fleeing towards the border with Somalia.
Last Sunday, three people were killed in a grenade attack at a night club in the port city of Mombasa, a day after the US embassy in Kenya warned of an imminent attack on the city.