Gunmen killed 10 people in an attack on a market and a church in northeast Nigeria before fleeing over the border to Cameroon, police said on Monday.
The attack took place on Sunday in the farming village of Njilang, Adamawa state, near the border, an area that has become a haven for Islamist sect Boko Haram.
"The gunmen opened fire in the village market, killing six persons, then proceeded to the church and opened fire there too, killing four more," Adamawa state police spokesman Mohammed Ibrahim said by telephone.
Nine others were being treated in hospital for wounds.
Ibrahim did not know who the culprits were. Although much of northeast Nigeria is plagued by Islamist militants, criminal gangs and ethnic militias also operate there.
The Boko Haram sect and offshoots such as the al-Qaida-linked Ansaru, as well as criminal networks, are seen as the main threat to stability in Nigeria, Africa's biggest energy producer. Its favourite targets have been churches, security forces and moderate Islamic clerics.
Violence in the north, particularly along the area where it borders Cameroon, Niger and Chad, shows no sign of letting up.
President Goodluck Jonathan has set up a committee to work out the terms of an amnesty for the rebels but their leader, Abubakar Shekau, has shown no interest in it so far.