A Muslim religious leader, who had previously criticised Boko Haram, and a Christian preacher have been killed in northern Nigeria in separate attacks blamed on the armed group.

Shaikh Adam Albani's car came under fire at 10:30pm on Saturday in Zaria, as he drove home from teaching a theology class, the AFP news agency reported on Sunday.

Local resident Mohammed Usman said Albani's wife and son were hit, while the gunmen appeared to have dragged him from the car and shot him at close range.

"We kept hearing gunshots very close to our homes and later we heard the sound of a car retreating and when we later came to the scene we found Sheikh Albani lying outside the car with lots of bullet holes on him," Usman said.

"He was still alive but his wife and a child she was holding in the front seat were already dead while the rest of the children sitting in the back seat were unharmed."

Albani had been critical of Boko Haram and supported a Nigerian military campaign against the group.

Rushed to hospital

Albani's brother Kaburu Adam said the religious leader died shortly after being admitted to a hospital.

In a separate incident, gunmen killed a pastor in an attack on a church in Sabon Garin Yambdula, in the Madagali area of Adamawa state late on Friday.

Ten people tried to repel the attack with hunting rifles, said Madagali local government chairman Maina Ularamu, according to AFP.

"All we know is that the gunmen were not soldiers, although they were dressed in military uniform, because some of them wore bathroom slippers instead of boots," he said. Others had their faces covered, he added.

The attackers stole four cows and also killed two goats, said Ularamu, who declined to say whether Boko Haram fighters were responsible.

The attack came after 26 people, most of them worshippers, were killed in a Roman Catholic Church in Waga Chakawa, also in Madagali, last Sunday, and a roadside bomb that killed seven people.

The Nigerian government has been battling Boko Haram, designated as a terrorist organisation by the United States, since 2009 and last May declared a state of emergency in three northeastern states of Adamawa, Borno and Yobe to rein in the fighters.

But attacks often targeting Christians and educational institutions have continued amid accusations against security forces of human rights abuses perpetrated against civilians.

Source: Agencies