A reinforced contingent of U.S. troops backed by mechanized forces will stay in northeastern Syria to protect oil fields from falling into the hands of a resurgent Islamic State, Defense Secretary Mark Esper said Friday.
"We are reinforcing that position" in the area of the oil fields in eastern Syria, Esper said at a news conference at NATO Headquarters in Brussels. "It will include some mechanized forces."
"I'm not going to get into the details, but the mission in Syria remains what the mission in Syria began with. It's always been about defeating [ISIS]. That is the core mission," he added.
It was not immediately clear whether the reference to "mechanized forces" was to Bradley Fighting Vehicles or M1 Abrams main battle tanks.
Related: Russia Says it Sent Hundreds of Additional Troops to Syria
It was also not clear where the mechanized forces would come from, but there is a U.S. armored brigade in Kuwait that has both tanks and Bradleys.
The still-evolving plan for a stay-behind force was among the recommendations made by Esper to President Donald Trump to "ensure the ongoing success of the defeat ISIS mission in Syria," a defense official said in a statement late Thursday.
How many U.S. troops will be deployed for the new mission in the chaotic region, and whether they will be drawn from among the several hundred troops that have already been pulled out of Syria into Iraq, was not specified.
The additional "assets" would appear to be headed to the oil field areas of Deir al-Zour, near the Iraqi border still controlled by the Kurdish-led Syrian Democratic Forces.
Earlier this week, Trump said at the White House that he wanted to "keep the oil" for the U.S.
"We'll work something out with the Kurds so that they have some money, so that they have some cash flow. Maybe we'll get one of our big oil companies to go in and do it properly," he said.
Esper then told reporters traveling with him to NATO meetings in Brussels that "we're looking [at] maybe keeping some additional forces" in Syria to guard oil wells, "but that needs to be worked out in time."
In a tweet Thursday, Trump appeared to greenlight the oil field deployments: "We will NEVER let a reconstituted ISIS have those fields."
The defense official said in the statement later Thursday, "One of the most significant gains by the U.S. and our partners in the fight against ISIS was gaining control of oil fields in eastern Syria -- a crucial source of revenue for ISIS.
"The U.S. is committed to reinforcing our position, in coordination with our SDF partners, in northeast Syria with additional military assets to prevent those oil fields from falling back into the hands of ISIS or other destabilizing actors," the official said.
In addition to the oil field mission in eastern Syria, the U.S. is also committed to maintaining the Al-Tanf garrison on the Jordanian border at the request of Israel and Jordan, both Trump and Esper said earlier this week.
Several hundred of the estimated 1,000 U.S. troops that had been in Syria were withdrawn into Iraq earlier this week under the initial plan to have them remain in the region to continue the fight against ISIS.
Some of the departing convoys were pelted with vegetables by residents shouting obscenities at them for leaving behind the partnered SDF fighters, who lost 11,000 killed and 23,000 wounded in the long campaign against ISIS, according to former Defense Secretary Jim Mattis.
A plan to have troops remain in Iraq in the Kurdish autonomous region was upended when Iraq's Defense Ministry said they had no permission to stay and would have to leave within four weeks. Esper later said they would eventually be brought back to the U.S.
The announcement of the oil field mission came amid reports from the region of renewed clashes between Turkey's military and the SDF in northeastern Syria, where Turkey's plan is to create a 20-mile deep "safe zone" for the return of Syrian refugees.
-- Richard Sisk can be reached at Richard.Sisk@Military.com.
Read more: Colonel Released from Brig as Child's Family Denounces Military Provision That Freed Him