At least 16 people have been killed after grenades were thrown at two churches in Kenya.
The attacks took place in the town of Garissa, close to the border with war-torn Somalia, as Sunday prayer services were being held.
As the congregations fled the explosions, the attackers opened fire, according to police.
"The goons were clad in balaclavas and hurled the grenades at the Catholic Church and the AIC (African Inland Church) in the town," regional deputy police chief Philip Ndolo said.
It is understood that up to seven men were involved in the attacks, which came two days after armed men killed a Kenyan driver and abducted four foreign aid workers from the nearby Dadaab refugee camp.
"We have not arrested any suspects, but we have reports that five suspects were involved in the AIC attack in a combination of grenade and shooting, while two suspects were involved in the Catholic church attack," Ndolo said.
Witnesses said that bodies lay scattered in the churches as scores of wounded were rushed to hospital.
"It is a terrible scene, you can see bodies lying in the churches," regional police chief Leo Nyongesa said.
He said the attackers had wrested guns from police who have been posted outside churches following previous attacks.
It was not clear who was behind the latest killings but Nairobi has blamed similar attacks on members or supporters of Somalia's al Qaeda-linked Shabaab fighters.
The attacks are the latest in a string of assaults since Kenya sent its troops into its troubled neighbour to target areas controlled by the hardline Islamist group.
Journalist William Davis, who is in the Kenyan capital of Nairobi, said: "So far, no group has claimed responsibility but it’s likely to have been carried out by the Islamic militants Al Shabaab.
"They control vast chunks of neighbouring Somalia and they’ve claimed responsibility for other attacks across Kenya in recent months.
"This is a lawless state and it’s very easy for these Islamic militants to get around and to cross over into Kenya."
The Supreme Council of Kenya Muslims condemned the attacks, saying that "all places of worship must be respected".