According to local residents, the fatalities occurred shortly after morning service on Sunday in the village of Kwamjilari, located about 30 kilometers east of the town of Chibok, in Borno state.
"Some of the worshipers remained around the church and the gunmen opened fire and eight men died," said Luka Damina, a resident from a nearby village.
He noted that the gunmen had stationed some of their comrades on the road leading out of the village and they shot anyone who tried to flee.
"Many people ran into the bush with gunshot wounds," Damina added.
A local chief from nearby Kautikeri village, where some locals fled, confirmed the death toll, adding that the assailants had set fire to homes and fields of maize that were almost ready for harvest.
In a similar attack in the area last month, at least 10 people lost their lives and some 13 others were abducted after the assailants looted and torched houses.
Boko Haram started its campaign of militancy in 2009 with the aim of toppling the central government in Nigeria.
The violence sparked by the group’s militancy has so far killed more than 20,000 people and forced over 2.7 million others from their homes.
The militant group has expanded its terror activities to Nigeria’s neighboring countries. Troops from Nigeria, Chad, Cameroon and Niger have been battling the terrorists in recent months.
The group has pledged allegiance to the Daesh Takfiri terrorists operating mainly in Syria and Iraq.