Niger has declared two days of national mourning from Friday, after at least 69 people were killed in an attack by suspected Islamist insurgents.

The attack happened in the country's south-west, near the border with Mali.

Victims included a local mayor and the leader of a self-defence militia, the government said. A search is underway for survivors.

No group has claimed responsibility for the bloodshed, which took place on Tuesday.

The assailants fled across the border into Mali, reportedly taking their own dead away with them.

Niger's interior ministry said a delegation led by the mayor of Banibangou had been ambushed at a village about 55km (32 miles) away, in the western Tillaberi region. In a statement, it blamed "unidentified armed bandits".

The area is overrun by militants associated with a local affiliate of the so-called Islamic State group.

Niger is facing jihadist insurgencies on its borders with Mali, Burkina Faso, and Nigeria. More than 500 people have been killed in insurgent violence this year in the country's south-west.

In March, some 137 people were killed during co-ordinated raids on three villages by suspected jihadists.