Gunmen have killed at least 20 people in Nigeria's Borno state, in two attacks suspected to be the work of militant sect Boko Haram.
The attacks appear to be reprisals against civilians who have formed anti-Boko Haram vigilante groups and are cooperating with the Nigerian military's Joint Task Force (JTF).
A Nigerian security source says that late Monday, gunmen shot six members of the civilian JTF as they slept in the town of Damasak. A civilian JTF spokesman confirmed the deaths and said the men ranged in age from 20 to 36.
The killings came a day after suspected Boko Haram gunmen killed 14 members of the vigilante group in the city of Bama.
The chairman of the Bama council said the victims were apparently lured into a trap by the attackers, who he said were dressed in army uniforms.
Bama is surrounded by a forest where Boko Haram members are believed to be hiding out, three months into an ongoing military offensive against the group.
In May, Boko Haram fighters burned down several government buildings in Bama and killed more than 50 people, including 22 policemen.
A week later, President Goodluck Jonathan declared a state of emergency in three northeastern states and sent thousands of additional troops to combat Boko Haram.
The Islamist group has carried out dozens of deadly attacks since launching an uprising in 2009, and is blamed for thousands of deaths. Rights groups say the military has killed hundreds more through indiscriminate and heavy-handed counter-attacks.