An Al Qaeda-linked group active in West Africa's Sahel region has claimed responsibility for an attack on a military base in Mali on Sunday that two sources said had killed more than 30 soldiers.

More than 400 soldiers have reportedly been killed by militants since the start of May in bases and towns in Mali, Niger and Burkina Faso.

The JNIM group said in a statement on Sunday that it had seized the base in Boulkessi in central Mali, near the border with Burkina Faso.

The Malian army said it had been forced to pull back.

"Many men fought, some until their last breath, to defend the Malian nation," its statement said, without giving any casualty numbers.

A spokesperson did not respond to a question about the toll, but two security sources said more than 30 soldiers had been killed.

A municipal source at Mondoro, near the base, said the insurgents "cleared the camp" and that there were many dead.

Recent attacks

Videos shared online showed dozens of insurgents overrunning the base.

JNIM has claimed responsibility for a host of recent attacks in the region.

On May 24, it said it had attacked a base in Dioura, central Mali, killing 40 soldiers.

Last Friday, it said it had seized a base in Sirakorola in southwestern Mali, although the army said it had repelled the attack. It did not provide a toll for that incident either.

In neighbouring Burkina Faso, JNIM claimed attacks on military positions and the town of Djibo in mid-May, in which it said it had killed 200 soldiers.

And in Niger, more than 100 soldiers were killed in two attacks in the Tahoua region on May 24 and the Dosso region on May 26, security sources said.

Neither Burkina Faso nor Niger has published an official death toll.