The French Defense Ministry says troops from France and Niger killed three armed combattants and detained three others who tried to force their way through a checkpoint near the Libyan border.

The ministry said Monday that the clash happened Thursday in the Salvador pass region near Manama, Niger, where the two countries began a joint counterterrorism operation on May 9.

The incident took place when two pickup trucks sought to force their way through a checkpoint, with armed fighters on board opening fire after troops fired warning shots.

The ministry said that afterward, 1.5 tons of drugs, which were unspecified, and automatic weapons were seized.

France has deployed 3,000 troops in a vast counterterrorism operation along with five countries in Africa's vast Sahel region along the southern Sahara.