UNITED NATIONS (AP) — Twenty-two U.N. peacekeepers in a convoy withdrawing from a rebel stronghold in northern Mali were injured when their vehicles hit improvised explosive devices on two occasions on Saturday, the United Nations said Monday.

There have now been six incidents since the peacekeepers left their base in Kidal on Oct. 31 for the estimated 350 kilometer (220-mile) trip to Gao, injuring a total of at least 39 peacekeepers, U.N. spokesman Stephane Dujarric said.

Eight peacekeepers were injured by improvised explosive devices last Wednesday and seven early Friday, he said, and at least two peacekeepers were injured in two earlier IED attacks.

Dujarric said the 22 peacekeepers injured Saturday had to be evacuated by air to receive treatment in Gao.

In June, Mali’s military junta, which overthrew the democratically elected president in 2021, ordered the nearly 15,000-strong U.N. peacekeeping force known as MINUSMA to leave after a decade of working on stemming a jihadi insurgency.

The U.N. Security Council terminated the mission’s mandate June 30 and the U.N. is in the throes of what Secretary-General António Guterres calls an “unprecedented” six-month exit from Mali by Dec. 31.

MINUSMA was one of the most dangerous U.N. peacekeeping operations in the world, with more than 300 members killed since operations began in 2013.

About 850 U.N. peacekeepers had been based in Kidal along with 150 other mission personnel. An employee with MINUSMA earlier told The Associated Press that the peacekeepers left Kidal in convoys after Mali’s junta refused to authorize flights to repatriate U.N. equipment and civilian personnel.

JNIM, an extremist group with links to al-Qaida, has claimed responsibility for the two earlier attacks. But Dujarric has said the U.N. doesn’t know if the IEDs that hit the convoy had been there for a long time or whether the peacekeepers were deliberately targeted.