Two U.S. F-15E fighter jets launched airstrikes Wednesday to destroy ammunition that was left behind when American forces abandoned a cement factory south of Kobani, Syria.

The factory had served as a coordination center for the U.S.-led coalition and Kurdish forces in the fight against the Islamic State group.

U.S. Army Col. Myles Caggins, a spokesman for the coalition, says the attacks by the Strike Eagle fighter jets were pre-planned and destroyed ammunition stored at the Lafarge Cement Factory.

All coalition personnel and “essential tactical equipment” had left the base before the strike, he said.

Most of the 1,000 U.S. forces in Syria are being withdrawn over the coming days and weeks as the Turkish invasion into northern Syria and the attack on Kurdish forces continues.