Hassan Chibok, a rescue team leader, said 12 bodies were found during rescue operation in Chibok town but the death toll might increase afterwards. The number of injured people so far rescued has reached 28.
Two unnamed security officers told Xinhua five suicide bombers were suspected to have entered Chibok on its weekly market day but only three detonated their improvised explosive devices, wreaking havoc on the town.
The two other suspected suicide bombers, yet to be apprehended, immediately fled the scene, the security officers said.
One of the bombers detonated an improvised explosive device right inside a local market, said a witness identified as Manasseh Hassan.
Another bomber blew himself up at a security checkpoint, hitting a "soft target", while the third bomber detonated his improvised explosive device near the same market, out of fear of being lynched.
Local residents are blaming the attack on Boko Haram, a terror group which has proved to be a hard nut to crack in Nigeria since 2009.
More than 200 school girls were abducted from Chibok town 21 months ago by Boko Haram. The abduction has aroused international outrage.
None of the missing girls has been found, although government said it is making efforts to know their whereabouts and ensure their freedom.