Suspected Boko Haram extremists killed at least 65 people over the weekend in an attack on villagers gathered at a funeral in Nigeria, a local official said Sunday.

The motorbike-riding assailants opened fire on mourners returning to their village from a funeral in the surrounding Nganzai local government area Saturday afternoon. It marked the deadliest extremist attack against civilians in the northeastern region this year.

Muhammad Bulama, council chairman of the Nganzai local government area, told reporters 11 other civilians were wounded during the attack. He called it a reprisal after villagers and civilian defense forces fought off a Boko Haram ambush in the area two weeks ago, killing 11 extremists.

While there has been no immediate claim of responsibility for Saturday’s assault, Boko Haram has repeatedly carried out attacks in Borno state, the heartland of the Nigerian terrorist group’s 10-year insurgency.

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Nigerians last week marked the grim 10-year anniversary of the Boko Haram insurgency, which has killed tens of thousands of people, displaced millions and created one of the world’s largest humanitarian crises. The extremists are known for mass abductions of schoolgirls and putting young women and men into suicide vests for attacks on markets, mosques and other high-traffic areas.

Boko Haram, who seeks to impose a strict Islamic state in the region, has defied the claims of President Muhammadu Buhari’s administration over the years that the insurgency has been crushed. The violence also has spilled into neighboring Chad, Niger and Cameroon.

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Nigeria’s military did not immediately comment on Saturday’s attack, but Bunu Bakar, secretary of self-defense group Borno Hunters Association, said he and his colleagues recovered nearly two dozen bodies after the attack.

Fox News' Morgan Cheung and the Associated Press contributed to this report.