"Two suicide bombers blew themselves up in two districts of Waza" on the Nigerian border last night, a security source who did not wish to be named, said.
State radio confirmed the report, saying two assailants detonated explosives, "killing six people, including themselves".
The victims included civilian vigilantes who were trained by the community to guard Waza against attacks, the security source said.
The attacks have been blamed on Boko Haram, a radical Sunni jihadist group seeking to create a hardline Islamic state in northeast Nigeria.
Over the past year Boko Haram has stepped up cross-border attacks in Niger, Chad and Cameroon while also continuing to mount shooting and suicide assaults on markets, mosques and other mostly civilian targets within Nigeria itself.