Islamist Boko Haram militants killed 159 people in two roadside attacks in northeast Nigeria this week, officials said, far more than was originally reported and a sign that a four-month-old army offensive has yet to stabilize the region.
In the first attack, on Tuesday, Boko Haram guerrillas wearing army uniforms stopped traffic on a highway between the cities of Maiduguri and Damaturu, dragging people out of their vehicles and killing them, with 143 bodies recovered so far.
Violence in northeast Nigeria has intensified over the past two months, as the armed group fights back against a military operation that President Goodluck Jonathan ordered in May to try to crush their four-year-old rebellion.
Tuesday's toll was initially given as "more than 20", but information often takes days to trickle out of the remote and sparsely populated region, where roads are bad, curfews are in force and the military has cut the phone network since May.
"We have been picking corpses off the roadsides all day, there are more in the bush," said Abdulazeez Kolomi, an Environmental Protection Agency official in Benisheik village.
"They are all travelers slaughtered by Boko Haram gunmen. We have so far picked up 143 corpses."
On Thursday, following a similar pattern, Boko Haram insurgents killed at least 16 people in an attack on travelers plying a highway from Maiduguri to Bamboa, a police source collecting bodies on the scene told Reuters.
Thousands of people have been killed since the armed group launched its uprising against the state in 2009, turning itself from a clerical movement opposed to Western culture into an armed militia with growing links to al Qaeda's West African wing.
Boko Haram aims to create an Islamic state in Nigeria and has waged a deadly insurgency since 2009. Officials have encouraged local vigilante groups to fight back against Boko Haram. Dozens of volunteers have been killed in the fighting in recent weeks.
Borno's Governor Kashim Shettima, who visited the scene of the attack on Thursday, described the killings as "barbaric and un-Islamic." He pledged financial assistance to relatives of the victims.
The town of Benisheik lies 45 miles west of the state capital of Maiduguri, where Boko Haram was founded in 2002.
Observers say Boko Haram may be taking revenge on vigilante groups. This has added to worries that encouraging people to fight back may escalate violence in the area.