U.S. troops and armored vehicles entered Syria Thursday determined to protect oil fields from falling under the hands of Islamic State terrorists, as indicated by a U.S. official.

Many warriors and less than 10 Bradley armored vehicles moved into the northeastern part of Syria, said the official, who was not authorized to talk publicly. It’s not clear what number of troops or vehicles eventually will be deployed, the official said.

The deployment comes not exactly seven days after President Trump ordered the raid that killed Abu Bakr al-Baghdadi, the founder of the Islamic State, otherwise called ISIS. U.S. commandos utilized a base in Syria to mount the attack by helicopter.

On Thursday, the representative for the U.S.- led coalition battling ISIS tweeted photographs of troops loading Bradley vehicles aboard aircraft for the mission in Syria. It is the first time in the five-year war on ISIS that American armor has been utilized to battle the extremists. The U.S.- led coalition has depended fundamentally on airstrikes to help nearby forces on the ground.

The region in northeastern Syria is home to oil wealth that Pentagon authorities and Trump have pledged to keep from falling under the hands of ISIS. The movement of troops and armor is the most recent in Trump’s whip-sawing strategy for Syria. In December 2018, he ordered a full withdrawal of the 2,000 troops who had been in Syria advising and battling close by for the most part Kurdish forces who had routed ISIS.

That declaration prompted the resignation of then-Defense Secretary Jim Mattis, and Trump yielded to pressure from Congress to keep up a force of around 1,000 soldiers in the nation. On Oct. 6, Trump ordered a withdrawal of virtually all U.S. troops from Syria, making ready for Turkey to press an attack against Kurds whom the Turks think about terrorists.

Congress again raised alarms, considering it a betrayal of the Kurds that risked unleashing chaos in the region, to the advantage of Russia and Iran.

Marine Gen. Kenneth McKenzie, who leads U.S. Headquarters, told reporters Wednesday that keeping oil fields from ISIS chokes off revenue the group needs to mount a comeback.

“What we want to do is ensure that ISIS is not able to regain possession of any of the oil fields that would allow them to gain income going forward,” McKenzie said. “So that’s – we’ve got forces at Deir Ez-Zor, that is – we have brought in some reinforcements there. We’ll await further decisions of the U.S. government about how that plan is going to look in the long term.”