As a US-led barrage of missiles rained down on suspected Syrian chemical weapons sites this weekend, Joint Chiefs Chairman Joseph Dunford said the Pentagon would be taking greater precautions to protect 2,000 American troops on the ground.

The strikes came as US troops, whom the Pentagon says are in-country to stop the resurgence of the Islamic State, already face increasing risks of getting enmeshed in the wider civil war. Military commanders are particularly worried about the rising risk of an unintended confrontation with Russia, especially after a deadly clash with Russian mercenaries in February.

“The commander always takes prudent measures, especially in an environment that they were in tonight,” Dunford told reporters at the Pentagon. “So they did make adjustments.”

Ahead of the strikes, the Pentagon reportedly pushed back against more expansive options favored by the White House in a weeklong bureaucratic tug-of-war. Dunford and Defense Secretary James Mattis raised concerns that US troops would be vulnerable to Russian or Syrian retaliation.