US aircraft strikes pro-Assad forces in Syria The strike hit a convoy near a U.S. coalition facility in al-Tanf.

 -- A U.S. aircraft conducted an airstrike Thursday on a pro-Assad regime militia convoy that appeared to be moving on a U.S. coalition training base in southeastern Syria, according to a U.S. official. A tank and several other vehicles were destroyed in the airstrike after the convoy ignored repeated warnings.

The airstrike occurred after a convoy of pro-Assad militia forces appeared to be headed toward at-Tanf, a town located near Syria's southeastern border with Iraq, according to the U.S. official. The U.S.-led coalition operates a training facility there for Syrian opposition forces fighting ISIS.

The pro-regime convoy had entered a so-called de-confliction zone to the northwest of at-Tanf and had apparently ignored Russian requests to turn away.

The coalition then dispatched aircraft to the area after it was deemed the convoy posed a threat to the coalition training facility.

Coalition aircraft flew a "show of force" above the convoy as a deterrent. When that did not work, warning shots were fired.

The aircraft dropped multiple munitions, destroying a tank and several other vehicles including bulldozers and front-end loaders, when the convoy moved closer.

In April, ISIS attacked the same garrison at al-Tanf, a move that also required coalition airstrikes.

Defense Secretary Jim Mattis later said the airstrike did not signal a growing U.S. military role in Syria.

"We're not increasing our role in the Syrian civil war but we will defend our troops, and that is a coalition element made up of more than just U.S. troops, and so we'll defend ourselves," Mattis said prior to a meeting with the Swedish defense minister.