A suicide bomber killed 14 people in northeast Nigeria, the state emergency agency said on Saturday, in an attack that bore the hallmarks of Boko Haram, days after a resurgence in the group's activities prompted a shift in military tactics.
A suicide bomber detonated the explosives in Dikwa on Friday night, after entering a building housing people who had previously fled the rebellion by Boko Haram and since returned, the State Emergency Management Agency (SEMA) said.
"We have so far evacuated 38 victims comprising 14 dead and 24 injured", said SEMA spokesman Bello Dambatta. Dikwa is around 90 kilometres east of Maiduguri, the capital of Borno state.
Volunteers said at least two dozen others were wounded and had to wait until Saturday morning to be evacuated because of safety concerns and the lack of phone service.
The attack brings the number of people killed by fighters in northeast Nigeria since June 1 to at least 113 and came days after suspected members of the group attacked and kidnapped an oil prospecting team, prompting a rescue bid that ended in the deaths of at least 37 people including members of the team and rescuers from the military and armed volunteers, officials say.
The group were part of a Nigerian National Petroleum Corporation team on a mission to find commercial quantities of oil in the Lake Chad basin.
The unofficial death toll is much higher. An aid agency worker involved in the recovery of bodies after the attack in the Magumeri area of Borno state on Tuesday told AFP news agency that so far the death toll was 69.
The worker, who asked not to be identified because he was not authorised to speak to the media, said 19 soldiers, 33 civilian volunteer fighters and 17 civilians were killed.
Another source with knowledge of the rescue operation gave the death toll as "70 or more" and also said it was unclear whether all the victims had been accounted for.
News of the rising death toll came after Boko Haram published a four-minute video in which three men kidnapped men from the oil prospecting team identified themselves as being from the University of Maiduguri.
University of Maiduguri spokesman Danjuma Gambo confirmed the identities of the three kidnapped men in the video to AFP.
At least five members of staff from the university - two lecturers, two technologists and a driver - were killed, vice-chancellor Ibrahim Njodi said on Friday.
He told reporters the university had been hesitant to send staff with the NNPC team but had been assured about security.
Boko Haram stepping up attacks
"It's a confirmation of the boldness and reassurance that Boko Haram has managed to gain over the last six weeks," Yan St-Pierre, from the Modern Security Consulting Group, told AFP.
"They have been attacking more and more military outposts and more military convoys. For them to go after NNPC personnel just shows they don't fear any military reprisal."
Nigeria is searching for oil in the northeast to try to reduce its reliance on supplies from the Niger Delta, where attacks have slashed production.
Boko Haram has stepped up the frequency of attacks in the last few months. The rebellion in the northeast of the country has killed 20,000 people and forced some 2.7 million to flee their homes in the last eight years.
After the kidnapping of the oil workers, Acting President Yemi Osinbajo on Thursday sent military chiefs to the northeast to help regain control of the situation.
The move was a change of tactics since the government and military have repeatedly said Boko Haram - which also carries out cross-border attacks in neighbouring Cameroon and Niger - was on the verge of being defeated.
President Muhammadu Buhari said in December that Boko Haram's stronghold in the northeast's vast Sambisa forest had been captured.
Source: News agencies