By Lanre Ola
MAIDUGURI, Nigeria, Nov 25 (Reuters) - Two female suicide bombers killed at least 44 people on Tuesday in Nigeria's northeastern city of Maiduguri, at the heart of a militant Islamist insurgency, medical officials said.
Four witnesses told Reuters near the scene a woman had entered the roadside trading area behind the city's main market before blowing herself up.
"While the people were trying to help the injured, the second bomb blasted," witness Sani Adamu told Reuters. "I saw lots of bodies."
A nurse at Maiduguri General Hospital said 42 bodies had been received from the twin blasts. In the Maiduguri University teaching hospital in a different part of town, a staff member said two of a dozen wounded brought there for treatment had so far died.
Nigerian authorities did not respond to requests for comment. There was no claim of responsibility, but suspicion is likely to fall on violent Islamist group Boko Haram, whose five-year-old campaign for an Islamic state has killed thousands.
The group has increasingly used female suicide bombers.
In June, there were four attacks by female bombers in the largely Muslim north, including one targeting a school in Kano, the region's biggest city. A woman blew herself up at a teacher training college in Nigeria's central Niger state on Nov. 12, killing at least one other person.
Boko Haram has stepped up assaults in the northeast of Nigeria, showing it remains the biggest security threat to Africa's biggest economy and top oil producer.
It has been trying to seize and hold on to territory with the apparent aim of carving a de facto Islamic state out of religiously-mixed Nigeria.
Boko Haram fighters seized control of remote Damasak town, around 180 km (110 miles) north of Maiduguri, on Monday. Residents said on Tuesday that Boko Haram fighters remained in control of the town.
Instability has spilled over into Nigeria's neighbors. A senior official at Cameroon's education ministry, Monouna Fotso, said on Tuesday it planned to close some 130 secondary schools near the Nigerian border. Schools are frequent targets for Boko Haram, whose name means "Western education is sinful."
Borno state, of which Maiduguri is the capital, has seen some of the fiercest fighting, although the city itself had not witnessed a suicide bombing since July.
Nigerian President Goodluck Jonathan plans to ask the national assembly to extend a state of emergency in the three northeastern states worst hit by the insurgency when it expires this month. (Reporting by Lanre Ola and Isaac Abrak, Writing by Tim Cocks and Julia Payne; Editing by Andrew Roche)