Gunmen in the north-western Nigerian state of Sokoto have killed at least 21 people in fresh attacks on several villages in Sabon Birni area.

Residents told the BBC that the attackers on motorbikes also looted food items and other essentials in the villages.

The raids were carried out on Tuesday night, with the village of Sangerawa being the worst hit.

The state's police spokesperson, Sanusi Abubakar, confirmed the killings but said they were still gathering details.

The attacks came as the state governor, Aminu Tambuwal, announced a rise in the death toll to 43 from a Monday attack in Illela town near the Niger border.

The authorities initially said 13 people had been shot dead there - and two others in Goronyo town.

North-western Nigeria has been grappling with armed criminal gangs carrying out killings and kidnappings for ransom.

The authorities are being criticised for failing to tackle the violence despite the deployment of thousands of security forces and the shutting down of internet and mobile phone services in most of the region.