Some 20 Malian soldiers were killed in an apparent jihadist attack Monday, local politicians and a military official said, in the latest bout of violence in the war-torn West African state.

Militants attacked a military base in the northern town of Bamba early on Monday morning, according to a local government official, who called the assailants "terrorists" and said at least 20 soldiers had died.

Another local official gave a similar account, explaining that the militants arrived on motorbikes and in cars. "Investigations are still ongoing on the ground because the death toll must be higher than the 20 deaths announced," the official said.

Mali has been struggling to contain a jihadist revolt that first broke out in the north in 2012, and which has since spread to the centre of the country and to neighbouring Burkina Faso and Niger. Thousands of Malian soldiers and civilians have died in the conflict to date, despite the presence of thousands of French and United Nations troops in the country.

It was not immediately clear who carried out Monday's attack. A Malian army official stationed in northern Mali confirmed that an attack had taken place in Bamba but said that there had been losses on both sides.

He added that the army did not have a clear idea of enemy losses, however, because the militants took their casualties with them when they left the area. Another military official told AFP that reinforcements had been dispatched to the area.