It was not clear who carried out the attack about 20km north of the town of Bambara-Maoudé in the Timbuktu region
Four United Nations peacekeepers were killed and five wounded in central Mali on Wednesday after a convoy struck an explosive device and came under fire, the UN said.
It was not clear who carried out the attack about 20km north of the town of Bambara-Maoudé in the Timbuktu region.
Islamist groups linked to al Qaeda and Islamic State operate in the region and have made much of the West African country ungovernable.
The UN mission in Mali, known as MINUSMA, said in a statement on Wednesday that three peacekeepers had been killed and six wounded in the attack. A MINUSMA spokesman said on Thursday that a fourth had since died.
The dead peacekeepers were from Ivory Coast, the country's defence ministry said in a statement.
The attack is the latest in a brutal conflict that has been raging in Mali since 2012, when jihadists overtook a rebellion by mostly ethnic Tuareg separatists in the north.
The conflict, which has killed thousands of soldiers and civilians to date, has since spread to central Mali as well as neighbouring Burkina Faso and Niger, inflaming ethnic tensions along the way.
Laying roadside bombs - or improvised explosive devices (IEDs) - is a favourite tactic among militants in the arid Sahel region.
France - which has 5,100 troops deployed across the Sahel - has lost five soldiers to IED attacks since late December.
First established in 2013, the 13,000-strong MINUSMA is the deadliest peacekeeping mission in the world. Over 230 of its personnel have died since the mission began.