These desertions alarmed Gaddafi, as the GUNT provided a cover of legitimacy to Libya's presence in Chad. To put a halt to these and reunite the GUNT, a major offensive was launched on the Red Line with the goal of taking N'Djamena. The attack, started on 10 February 1986, involved 5,000 Libyan and 5,000 GUNT troops, and concentrated on the FANT outposts of Kouba Olanga, Kalait and Oum Chalouba. The campaign ended in disaster for Gaddafi, when a FANT counteroffensive on 13 February using the new equipment obtained from the French forced the attackers to withdraw and reorganize.