Gunmen ambushed a convoy of traders travelling to a market under military escort and killed at least 20 people in Nigeria's northwestern Zamfara state, a witness and a military source said on Monday.
Local resident Musa Danladi told Reuters the attack occurred around 2 p.m. on Saturday with the convoy en route to Nasarawa market in Bukkuyum district from Gwashi.
Danladi, who helped retrieve the bodies, said four soldiers, three policemen and a Nigerian civil defence corps officer were among those killed, along with 12 civilians.
Northwestern Nigeria has seen a surge in attacks by heavily armed gangs, known as bandits, who raid villages, abduct residents for ransom and rustle livestock.
A military source confirmed the attack and said 19 people were also wounded.
Military and police authorities did not immediately respond to requests for comment.