The death toll from Friday’s attack on a remote village in the north-eastern Nigerian state of Taraba has risen to at least 48, police have told the BBC.

The police had initially reported 10 deaths after unidentified gunmen on motorcycles raided the village of Binnari, looting shops and setting houses ablaze.

More bodies were discovered on Sunday, according to state police spokesperson Victor Mshelizah, who said some of the victims had drowned while trying to escape the attackers while others were killed in nearby bushes.

Meanwhile, Amnesty International’s director for Nigeria said his organisation had confirmed 52 deaths, citing sources on the ground and members of the local community.

The attack happened just after midday Muslim prayers, and the rampage went on for up to four hours.

State police had initially recovered 10 bodies with gunshot wounds after officers responded to a distress call.

The attackers had fled by the time officers arrived – but they continued to patrol the area to restore calm, Taraba’s police told the BBC on Saturday.

“We were able to disperse the unknown gunmen though there was no casualty on their side and ours because the terrain is difficult and they’re used to the terrain,” Assistant Superintendent of Police Victor Mshelizah said.

Community leader Malam Abubakar Saifullahi told news agency AFP that the attackers had arrived on about 50 motorcycles, two men apiece.

“They looted shops and took cash, foodstuffs and other provisions,” he said. “They also took motorcycles abandoned by people fleeing the attack.”

Isiyaku Musa, who survived the attack, told AFP: “People were running in different directions to escape the attack. Nobody knew where it was safe to go.”

Amnesty’s Nigeria director Isa Sanusi has called for an impartial investigation into the killings, accusing the authorities of leaving rural communities “at the mercy of gunmen that are repeatedly commit atrocities with impunity”.

Parts of north-eastern Nigeria have been affected by years of violence involving jihadist groups and armed gangs, which raid communities, abduct residents and demand ransoms.

Similar armed groups operate in the country’s north-west and central regions.

The latest attack comes as Nigeria prepares for elections next year, with insecurity expected to feature prominently in political debates.