Just weeks after President Trump ordered the withdrawal of U.S. forces from Northern Syria, troops have returned to defend oil facilities from falling into the hands of the Islamic State. There were approximately 1,000 American troops in Northern Syria when President Trump announced, “It’s time to come back home,” earlier in October, but with this new deployment, American troop counts in the war-torn country are once again at around 700.

The 500 additional soldiers, along with M2A2 Bradley Fighting Vehicles, hail from the National Guard’s 30th Armored Brigade Combat Team, and will continue to partner with Kurdish forces in the region “to defeat ISIS remnants, protect critical infrastructure, and deny ISIS access to revenue sources,” according to Col. Myles Caggins on Twitter.

According to Chairman of the Joint Chiefs of Staff Gen. Mark Milley, American troops will be assigned to bolster defenses at the Conoco oil fields, located just east of Deir ez Zor in northeastern Syria.

Defense Secretary Mark Esper added that the deployment would go on until the United States has “sufficient capability to ensure ISIS and other destabilizing actors are denied access to that oil facility.” Esper went on to emphasize that while U.S. troops are there only to defend the oil facilities, they would “respond with overwhelming military force against any group who threatens the safety of our forces there.” The vague language used in that threat is seemingly a warning to Turkish, Russian, and Syrian troops now also operating in the region.

Last year, a group of Russian mercenaries fighting alongside Assad-backed Syrian forces attacked a position held by Kurdish troops and U.S. special operators. The U.S. military presence in the region responded swiftly, utterly annihilating the Russian troops thanks in no small part to air support provided by AH-64 Apaches and AC-130 gunships. The Russian government claimed to have no knowledge of the engagement, suggesting the Russian mercenaries were in Syria on their own accord and with no formal ties to their government.