Militants killed five United Nations soldiers on Thursday in Mali's restive northern desert, sources from the organisation's peacekeeping mission told AFP.

"Five peacekeepers from Burkina Faso were killed on Thursday between Timbuktu and Goundam, during an attack by terrorists," said a source in MINUSMA, the UN's force in the west African nation.

Another source within the mission said nine peacekeepers were wounded in the attack, which appeared to have been carried out by militants who were well-informed about the movements of the MINUSMA convoy.     

There was no immediate information on the nature of the attack, although roadside bombs and ambushes by militants armed with assault rifles are a commonplace hazard for domestic and international security forces in the region.

The UN says 35 peacekeepers have been killed in combat since MINUSMA's inception in 2013, not including Thursday's attack, making northern Mali the deadliest theatre on earth for its personnel.

The country's northern desert, a disputed region the size of France, has been plagued by violence from jihadist groups that seized control from Tuareg rebels before being routed by a French-led international intervention in 2013.

Despite peaceful elections after the French operation, the country remains deeply divided and the north has seen an upsurge in attacks recently by pro-government militias and the Tuareg-led rebellion known as the CMA.

The area around Goundam, a town of around 16,000 people some 100 kilometres (60 miles) southwest of Timbuktu, has seen much of the bloodshed, culminating in the killing of eight Malian soldiers in May by the rebels.