At least 25 people were killed in an attack by suspected Boko Haram jihadists on Monday afternoon and Tuesday morning on three communities in Nigeria's northeastern Borno state, military and police sources said.
Fighters in pick-up trucks attacked the town of Dille and two smaller communities in the Askira/Uba area in Borno state.
Vigilantes resisted the attack on Dille that came around 1pm local time (1200 GMT), the sources said.
A police source who declined to be named said the attacks on the smaller nearby communities came early on Tuesday.
Boko Haram has been trying to carve out an Islamist state in the northeast of Nigeria for the last six years. It controlled large swathes of territory in three states last year before being pushed out of the major towns it controlled.
The militants have dispersed into various pockets across Borno state, notably along the Niger border near Damasak, Lake Chad, the Sambisa forest reserve and around the Mandara mountain range that borders Cameroon.
Borno state governor Kashim Shettima said this month that seven local government areas out of 27 were "largely inaccessible because these lunatics called Boko Haram still move up and down the areas".
On Tuesday, the European Union said that about 800 people are reported to have been killed in the countries around Lake Chad.
Nigeria and its neighbours, increasingly targetted by the insurgents, are setting up new headquarters for their multi-national joint taskforce in Chad's N'Djamena.
A Reuters tally showed that more than 600 people had been killed in Nigeria alone since President Muhammadu Buhari's inauguration at the end of May, when he promised to make getting rid of Boko Haram his top priority.