People gather outside a church following a blast in Kaduna, Nigeria, Sunday, June 17, 2012. Three church blasts rocked a northern Nigerian state Sunday, officials said, prompting protests in a state that has previously been strained by religious tensions. (AP Photo/Olu Ajayi)

Zaria, Nigeria

Bombings at three churches in Nigeria’s northern Kaduna state killed at least seven people and wounded others yesterday, triggering retaliatory attacks by Christian youths who dragged Muslims from cars and killed them, officials and witnesses said.

There was no immediate claim of responsibility for the bombings but the Islamist Boko Haram group has often attacked church services in Nigeria, Africa’s most populous country and split roughly evenly between Christians and Muslims.

The bombings and retaliatory attacks stoked fears of wider sectarian conflict in Nigeria.

Kaduna state’s governor declared a 24-hour curfew in a bid to restore calm. Boko Haram, increasingly radicalised and meshed with other Islamist groups in the region, is the leading security threat to Nigeria.

Two blasts hit churches in the town of Zaria within minutes of each other. First, a suicide bomber drove a car into a church, its pastor said.

“Three people are confirmed killed. Others have been taken to hospital for treatment,” said the Rev Nathan Waziri.

Then, attackers threw bombs at another church, killing four children who were playing on the streets outside, said Deborah Osagie, who lives opposite the church. She said the attackers were later caught by a crowd and killed.

A blast hit a third church, called the Shalom Church, in the state’s main city of Kaduna.

“There are a number of injured and dead from the bombings. We don’t have precise figures yet,” said Musa Ilela, an official from the National Emergency Management Agency in Kaduna state.

After the bombings, Christian youths blocked the highway leading south out of Kaduna to the Nigerian capital, Abuja, pulling Muslims out of cars and killing them, witnesses said.

“We had to return home when we saw the Christian youths attacking. I saw many bodies on the ground, but I don’t know how many were dead or just injured,” said Kaduna resident Rafael Gwaza.

Witness Haruna Isah said up to 20 people might have been killed in reprisals at the roadblock.

“There were bodies everywhere on the ground,” he said.

Kaduna state governor Patrick Yakowa called for calm.

“In view of the incidents and the need to have complete normalcy and to forestall a further breakdown of law and order, the state government has imposed a 24-hour curfew in the whole state,” a statement from his office said.

Last Sunday, Islamist militants attacked two churches in Nigeria.

Boko Haram says it is fighting to reinstate an ancient Islamic caliphate that would adhere to strict sharia, or Islamic law.