A Syrian rebel commander said that a rare, eight-day period of military drills with U.S. marines in southern Syria, which concluded this week, provided a strong message to Iran and Russia that the United States and the rebels will combat any threats against themselves.

Col. Muhanad al-Talaa, commander of the Pentagon-backed Maghawir al Thawra group, or Revolutionary Commando Army, told Reuters that the drills were the first such exercises, including simulated air and ground assaults, consisting of hundreds of U.S. troops and rebel fighters.

“These exercises have a big importance, and have beefed up the defenses of the area and raised the combat capabilities and morale and that of civilians in the area,” al-Talaa told Reuters.

“We are staying, whether the Russians or Iranians want [it] or not,” he added.

U.S. Col. Sean Ryan said the drills were a demonstration of force, and that the Pentagon had notified Moscow through “deconfliction” channels to avert “miscommunication or escalate tension.”

He said “the exercise was conducted to reinforce our capabilities and ensure we are ready to respond to any threat to our forces within our area of operations.”