At least 40 farmers have been killed in recent attacks in Nigeria’s Borno State, according to Governor Babagana Umara Zulum.

The attacks are believed to have been carried out by extremists linked to Boko Haram, the group responsible for the ongoing insurgency in the region since 2009.

Governor Zulum has promised a thorough investigation and called on the military to take swift action against those responsible.

He also urged residents to remain in “safe zones” that have been cleared of threats by the military. Boko Haram’s insurgency has led to over 35,000 deaths and displaced more than 2 million people in northeast Nigeria, with neighboring countries also affected.