Troops Find 6-Ton Explosives Cache in Mali

French and Chadian troops have destroyed almost six tons of explosives and weapons found in Mali's rebel-infested desert north, the United Nations said on Monday.

The Chadian soldiers, from the U.N.'s MINUSMA peacekeeping mission, were patrolling an area near the Algerian border with troops from France's Operation Serval when they made the discovery, a U.N. statement said.

"On December 28 and 29 a Chadian MINUSMA battalion and its liaison and support detachment from the Serval force have unearthed two large caches of weapons and ammunition located about 150 kilometers (95 miles) southwest of Tessalit," the statement read.

France launched Operation Serval in January to drive out al-Qaida-linked extremists who had occupied Mali's north in 2012 and imposed a brutal interpretation of Islamic sharia on the inhabitants of Timbuktu and the other main desert settlements.

The statement said the destruction of 5.7 tons of ammonium nitrate and some 40 grenades had dealt "another severe blow to the resources of terrorist groups."

It is the second significant haul in three months, after French soldiers discovered and destroyed a vehicle containing nearly a tonne of explosives near the northeastern town of Anefis in September.

Operation Serval has weakened the various Islamist groups who occupied the former French colony for nine months last year but they remain active and the ever-present threat was underlined when two Senegalese peacekeepers were killed in a suicide bombing earlier this month.

The U.N.'s announcement came on the eve of the visit of French Defence Minister Jean-Yves Le Drian to Mali as part of a three-day tour focusing on security which also takes in Niger and Chad.