The death toll from an attack in northeastern Nigeria that saw insurgents dressed as soldiers set up checkpoints and gun down travellers on a highway has risen to at least 142, an official said Sunday.
"We recovered 55 bodies on Wednesday and 87 on Thursday," Abdulaziz Kolomi, an official with the environmental protection agency in Borno state where the attack occurred, told AFP. The previous toll from the attack late Tuesday in the Benisheik area was 87.
The insurgents, suspected to be from Islamist extremist group Boko Haram, also burned scores of homes and buildings in the assault and left corpses littering the roadside.
The motivation behind the assault was not immediately clear, but Boko Haram members have repeatedly carried out revenge attacks against residents over the emergence of vigilante groups that have formed to assist the military.
Benisheik was also the scene of deadly clashes on September 8 between suspected Boko Haram gunmen and vigilantes.
Residents described a gruesome assault on Tuesday, saying the attackers singled out people from Borno, while letting people from other regions pass through checkpoints.
One security source said in the wake of the attack that "they came in droves, driving about 20 pickup trucks."
Army General Mohammed Yusuf, who briefed the state governor on the attack, said troops ran out of ammunition while combatting the assault. He said the insurgents were armed with "anti-aircraft guns."
Northeastern Nigeria has seen an outburst of violence in recent days, leaving scores of people dead and casting doubt over the effectiveness of a military assault seeking to end Boko Haram's four-year insurgency.
The insurgents say they are fighting to create an Islamic state in Nigeria's mainly Muslim north, but their aims have repeatedly shifted and much of their recent violence has targeted defenceless civilians.
In mid-May, Nigeria declared a state of emergency across the northeast, Boko Haram's stronghold, and launched a sweeping offensive aimed at crushing the group's four-year insurgency.
While the military has claimed major successes in the campaign, the attacks may have simply shifted from cities to more remote areas.
The phone network in Borno has been switched off since the emergency measures were imposed, a move the military said was aimed at blocking the Islamists from coordinating attacks.
Some have suggested that the lack of phone service has prevented civilians from sounding the alarm during attacks. It has also made it difficult to verify information from the region.
The insurgency was estimated earlier this year to have killed at least 3,600 people since 2009, including deaths caused by the security services, but the current toll is likely much higher.
Nigeria is Africa's top oil producer and most populous country, roughly divided between a mainly Muslim north and predominately Christian south.