Suspected Boko Haram militants opened fire on a funeral in Nigeria’s north-eastern state of Borno, killing at least 30 people.
Eyewitnesses say militants on motorbikes and in vans opened fire on mourners in a village on the outskirts of the state capital, Maiduguri.
The death toll could be as high as 65, AFP news agency reports.
There has been an increase in attacks by Boko Haram and other Islamist groups in Nigeria and across the region.
Tens of thousands of civilians have been killed and more than two million displaced over the past decade of conflict.
Boko Haram was formed around 2002 as a non-violent organisation with the aim of purifying Islam in northern Nigeria, it became increasingly radicalised and eventually adopted militant tactics in pursuit of its aims.
It has been active not only in Nigeria, but also in the neighbouring countries of Chad, Niger and Cameroon.
The group has been notorious for kidnapping schoolchildren and attracted global media attention in 2014 following the abduction of almost 300 girls from a school in the town of Chibok, in Borno, the state where the militant group has been most active.
In 2015, Boko Haram was ranked the world’s deadliest terror group by the Institute for Economics and Peace.
Territory controlled by the group has declined in recent years and it has splintered into competing factions.
However, the Islamist militants remain active in the region, defying attempts by the army to bring the insurgency to an end.