Multiple suicide bomb blasts early Wednesday rocked a displaced persons' camp near Nigeria's northeastern city of Maiduguri, officials said.
The attacks killed at least four people and wounded 18 others. The camp is housing migrants who have fled Boko Haram insurgents.
The exact number of blasts is not clear but at least four explosions hit the restive city.
Borno Police Commissioner Damian Chukwu said, "Three bomb explosions occurred this morning 04:30 a.m. (0330 GMT) at three different locations near Muna Garage, Maiduguri."
He said two of the blasts happened at camps for people displaced by Boko Haram.
But a coordinator of the Muna camp Tijjani Lumani said, "There were four explosions inside the camp."
"The bombers struck at different locations around 4:30 am. The explosions triggered fires which burned down many tents," Lumani said.
Worst hit city in Nigeria
The attacks are the latest in a string of attacks in the last few days that bear the hallmarks of Boko Haram, which, since 2009, has killed around 15,000 people and forced more than 2 million people to flee their homes in Africa's most populous nation.
Three suicide bombers killed four people and injured eight others in a village near Maiduguri on Sunday. Maiduguri has been the city worst hit by Boko Haram's eight-year-old campaign in northeastern Nigeria.