Islamist militants have attacked a river boat in north-eastern Mali, killing at least 49 civilians, the interim government says.

They also reportedly attacked an army camp, killing 15 soldiers, while around 50 militants are said to have died.

The government has declared three days of national mourning.

The Islamist threat has been growing despite claims by the military that Russian Wagner Group mercenaries are turning the tide of their campaign.

The northern city of Timbuktu has been under blockade since the end of last month and there have been several other recent attacks on transport.

The BBC could not independently verify the government's latest report, which was read out on national TV.

Militants reportedly attacked the boat as it was traveling on the River Niger from the town of Gao to Mopti. The river is a key transport link in a region where there are few quality roads and no railways.

Militants also attacked an army camp in the Bourem Circle in the Gao region.

The Malian army said on social media that the boat had been attacked around 1100 GMT by "armed terrorist groups".

The al-Qaeda linked group, Jamaat Nusrat al-Islam wal-Muslimin (JNIM), said it had carried out the assault on the army camp but has not mentioned the boat attack. It is one of several Islamist groups operating in northern Mali and neighbouring countries.

The boat operator, Comanav, told AFP news agency the vessel had been targeted by at least three rockets aimed at its engines,

The vessel was immobilised on the river and the army went in to evacuate passengers, said a Comanav official, speaking on condition of anonymity.

Mali has been under the control of a military junta since 2020.

There was huge popular support for the junta when it seized power after mass protests against then-President Ibrahim Boubacar Keïta. People had been angered by economic uncertainty, a disputed election and chronic insecurity.

Since then, data suggests Mali's military government has made little progress in its fightback against Islamists who control parts of the country.

Mali's military authorities have ordered French troops and UN peacekeepers out of the country and invited Russian contractors to replace them.

An insurgency with links to al-Qaeda and Islamic State took root in the north of Mali in 2012. Islamist militants have since gained ground, spreading across the Sahel region, especially to Burkina Faso and Niger.