The airstrike occurred near a low-key training facility used by U.S. troops northwest of At Tanf, a town about 20 miles from the border, officials said. They described the aggressors as "pro-regime" but not directly associated with the Assad government — noting also that Russian military forces attempted unsuccessfully to call off the advancing convoy after it had crossed "well inside an established de-confliction zone."
Thursday's incident underscores, once again, the complex dynamic facing U.S. forces inside of war-torn Syria. It comes six weeks after President Donald Trump ordered a retaliatory attack on Assad's military for its alleged use of chemical weapons against civilians. At the time, U.S. officials accused Russia of being complicit but have since begun to work more closely with Moscow hoping to establish areas that are protected from violence. For now, both sides appear to be taking that seriously.
"We are not increasing our role in the Syrian civil war, but we will defend our troops," Defense Secretary Jim Mattis told reporters Thursday at the outset of a meeting with the Swedish defense minister.
This was despite #Russian attempts to dissuade pro-regime movement towards At Tanf, #Coalition aircraft show of force, & warning shots2/3
— Inherent Resolve (@CJTFOIR) May 18, 2017
Few details have emerged about the group targeted. Analysts have suggested a link to Hezbollah and Iran, which like Assad is unsettled by and unhappy with the American military presence in Syria. The U.S. and its regional allies, namely Jordan and Israel, are just as bothered by Iranian activity so close to their borders.
"The pro-regime forces must now withdraw outside of the established de-confliction zone to avert further coalition action and remove the threat to our forces," U.S. officials said. "Coalition forces will continue to defend themselves against ISIS or any other threat to coalition or partnered forces in the area."
De-confliction zones are U.S. military parlance for areas inside Syria where the U.S. and Russia have agreed not to impede one another's activity. Thursday's incident involved two breaches, according to The New York Times, which reported that F-22 fighters were dispatched to scare off a Syrian SU-22 fighter-bomber.
U.S. officials indicated the ground threat included tanks, armored vehicles, artillery and pickup trucks equipped with heavy machine guns. The U.S. aircraft flew low and close to the convoy as a show of force before firing warning shots and, finally, unleashing the targeted attack.
It's unclear whether anyone was killed or wounded. Officials have said only that a tank was destroyed along with some construction equipment.
But some clandestine American units are training entities who oppose Assad as well, and it's believed some of that work occurs in At Tanf. The border town is the site of significant activity dating back more than a year. Just last month, for instance, ISIS militants attacked a facility housing U.S. special operations forces as they trained opposition fighters. With the aid of airstrikes, the Americans repelled the attack, killing between 20 and 30 attackers.
Loyalists (red) have been pushing along international highway to cut US-backed FSA (green) from advancing into Syria from Tanf crossing. /4 pic.twitter.com/RMiuVHSzna
— Tobias Schneider (@tobiaschneider) May 18, 2017
Many analysts believe the town is a transfer station connecting the Syrian government with its supporters in Iran, Iraq and Lebanon, where Hezbollah is based. Linking the corridor would provide a stable land transit route to resupply the regime and bolster its proxies.
"The stated intent of that pro-regime convoy was to reopen the Damascus-Baghdad highway," said Jennifer Cafarella, a Syria expert at the Institute for the Study of War. "I think [they] intended to test U.S. resolve and found it appropriately intact when it comes to force protection."
Andrew deGrandpre is Military Times’ senior editor and Pentagon bureau chief. On Twitter: @adegrandpre. Shawn Snow is a staff writer and Military Times' Early Bird editor. On Twitter: @SnowSox184.