Islamist militants killed at least 44 civilians and severely injured 13 others during an attack on a mosque in southwest Niger on Friday, the country's defence ministry said.

The attack occurred during afternoon prayers in the village of Fombita in the rural commune of Kokorou, which is near the tri-border region of Niger, Burkina Faso and Mali known as the epicentre of a jihadist insurgency in West Africa linked to al Qaeda and Islamic State.

The defence ministry blamed the attack on the EIGS group, an Islamic State affiliate, in a statement late on Friday.

Reuters is not able to contact EIGS for comment.

Heavily armed jihadists encircled a mosque, where people had gathered for prayers during the Muslim holy month of Ramadan, and carried out a "massacre of rare cruelty", it said.

The attackers then set fire to a market and houses before retreating, the ministry said.

Troops deployed to the scene provided a provisional death toll of 44 civilians, with 13 severely injured. Three days of national mourning have been declared.

The insurgency in West Africa's Sahel region started when Islamist militants took over territory in north Mali after a 2012 Tuareg rebellion.

It has since spread into neighbouring Niger and Burkina Faso, and more recently into the north of coastal West African countries such as Togo and Ghana.

Hundreds of thousands have been killed and millions displaced as militants have gained groups, attacking towns, villages, military and police posts and army convoys.

The failure of governments to restore security contributed to two coups in Mali, two in Burkina Faso and one in Niger between 2020 and 2023. All three remain under military rule despite regional and international pressure to hold elections.