The attacks took place on Wednesday in the Biu community of Kebbi state, police spokesman Bashir Usman said late on Thursday.
The assailants crossed from Sokoto state, parts of which were occupied by the Lakurawa insurgent group, Usman said.
"Preliminary investigations confirm that armed Lakurawa militants entered the area to rustle cattle," he said, adding that security personnel had been deployed to restore calm and maintain order.
The Lakurawa group operates in parts of northwestern Nigeria, particularly around communities in the northwestern state of Sokoto.
The armed group is known to engage in cattle theft, raids on villages and kidnappings for ransom.
Northern Nigeria is in the grip of a complex security crisis featuring both Islamic militants and armed criminal gangs kidnapping people for ransom.
The West African nation is in security co-operation with the US after initial diplomatic tensions.
Earlier this week, the Nigerian military announced the arrival of 100 US troops in Nigeria to help train its military in its fight against armed groups.
20°C