The operation was prompted by the invasion of Chad by a joint force of Libyan units and Chadian Transitional Government of National Unity (GUNT) rebels in June 1983.

To end this stalemate, French President François Mitterrand and Libyan leader Muammar Gaddafi negotiated a mutual withdrawal of their countries' troops from Chad in September 1984.

Chad had been involved in a civil war since 1965, which reached its most dramatic phase in 1979 when a fragile alliance between the President Félix Malloum and the Prime Minister Hissène Habré collapsed, unleashing factional politics.

[2] Refusing to acknowledge Habré as the new Chadian President, Goukouni refounded the GUNT as an anti-Habré coalition of armed groups in October in the town of Bardaï.

[5] Gaddafi, judging the time to be ripe for a decisive offensive, ordered a massive joint GUNT-Libyan attack against Faya-Largeau, the main government stronghold in northern Chad, during June 1983.

The fall of the city on June 24 generated a crisis in Franco-Libyan relations, with the French Foreign Minister Claude Cheysson announcing that day that France "would not remain indifferent" to Libya's intervention in Chad.

[6] The 3,000 man-strong GUNT force continued its advance towards Koro Toro, Oum Chalouba and Abéché, the main city in eastern Chad, which fell on July 8.

These victories gave Goukouni and Gaddafi control of the main routes from the north to N'Djamena,[3][7] and also severed Habré's supply line to Sudan.

Thus assisted, and taking advantage of the GUNT's overextended supply line, Habré took personal command of the Chadian National Armed Forces (FANT) and drove Goukouni's army out of Abéché four days after the city's fall.

Habré, who entrenched himself in Faya-Largeau with 5,000 troops, could not match the massive Libyan firepower, losing a third of his army and being forced out of Faya and retreating 200 miles south.

It was only a question of time before rifts would start emerging between the Libyan military and the GUNT forces, due to Libya's inability to balance the demands from these two groups.

He felt the French ought to retaliate by striking the GUNT at Faya-Largeau, which would have served as a declaration of war on Libya and escalated the conflict, something Mitterrand wanted to avoid at all costs.

While the advance was blocked, a Jaguar was shot down and its pilot killed, leading to the January 27 decision to move the Red Line from the 15th to the 16th parallel, running from Koro Toro to Oum Chalouba.

These rumors obligated the French Foreign Minister Roland Dumas to formally deny the existence of such clauses in the Franco-African summit held in Bujumbura in December.

These weakened the GUNT, which was increasingly divided by internal dissension and progressively estranged from the Libyans, who were pursuing a strategy of annexation towards northern Chad.