Gunmen on motorcycles killed dozens of people in a string of attacks on villages in the restive northwest of Nigeria, as the authorities struggle to curb the violence. 

Gangs of armed criminals - known locally as "bandits” - raided five villages close to the border with Niger in Sokoto state late Wednesday, officials said.

Lawal Kakale, a local traditional leader in Sabon Birni district, said the death toll had risen to 74 from an earlier figure of 60 as more bodies were recovered in the villages. 

"We recovered 25 corpses in Garki, 13 in Dan Aduwa, 25 in Kuzari, seven in Katuma and four in Masawa," he told AFP. 

"People fled in all directions and were pursued by the attackers. So, the corpses were scattered."

Medics at the nearby hospital said they initially received 60 corpses with gunshot wounds in the wake of the assaults. 

"All the bodies had bullet wounds, most of them were shot in the head," a medic said on condition of anonymity. 

A regional police spokesman confirmed the attacks but gave no further details ahead of a statement due from commanders visiting the scene.  

Sokoto state governor Aminu Tambuwal said the attack by "hundreds" of gunmen came as a "rude shock" as security officials had recently visited the area to try to calm tensions. 

Northwestern Nigeria has been wracked by years of violence involving clashes between rival communities over land, attacks by heavily-armed criminal gangs and reprisal killings by vigilante groups.

Cattle rustling and kidnapping for ransom have flourished in the security vacuum.  

Sabon Birni district, 175 kilometres (110 miles) from the state capital Sokoto, has recently been repeatedly attacked by armed gangs. 

On Monday 18 people were killed when gunmen raided five other villages in Sabon Birni district, local officials said.

Nigeria's armed forces last week launched bombing raids against camps in neighbouring areas of the northwest as part of the latest efforts to curb attacks.

The army said the bombing campaign had killed hundreds of "bandits" but there has been no independent confirmation of the death tolls.

Authorities have previously launched repeated military operations and local peace talks to try to end the violence. 

But so far neither strategy has succeeded in halting unrest that has killed an estimated 8,000 people since 2011 and displaced 200,000. 

International Crisis Group warned last week that jihadist groups waging a decade-long insurgency in northeast Nigeria are gaining influence in the northwest of the country. 

Brussels-based researchers said the region risked becoming a "land bridge" to Islamist fighters across the Sahel. 

The group said there needed to be closer cooperation between the security forces in Nigeria and Niger to stop the flow of arms across their porous border. 

Local leaders in Sokoto have said residents increasingly look to soldiers from Niger for protection and accused Nigerian army of failing to respond to attacks. 

AFP