UN said Friday over 30 fishermen and farmers have been killed in a terror attack by Boko Haram in Nigeria's northeast Borno State.

Resident coordinator in Nigeria, Matthias Schmale, in a statement, said several others were injured and some were missing when the terrorists ambushed them at the remote Mukdolo village in Borno State.

"The United Nations strongly condemns the reported ambush and brutal killing of more than 30 civilians in Mukdolo village in Ngala Local Government Area in Borno State," he said.

He described the incident as deeply shocking, calling on the terrorists to respect international law.

Some residents told Anadolu that Mukdolo village had been abandoned by civilians for over a decade following previous terror activities in the area.

They said the victims went to the village to scavenge for scraps, twisted iron, and metal.

Borno Police Commissioner Abdu Umar earlier on Thursday told reporters that 26 people were killed in two separate attacks in the area same day -- 25 in the fishermen/farmers attack and a policeman in another incident.

"In Dikwa, Boko Haram killed 25 fishermen. One person was also injured," said Umar.

The attack on the fishermen was the first major incident in the region, which has experienced over a decade of terrorist activities by Boko Haram and its spin-off Islamic State West Africa Province (ISWAP).