The U.S. military on Friday dispatched two F-22 Raptor stealth fighter jets to intercept a pair of Syrian Su-24 Fencer aircraft that flew in the vicinity of Hasakah, Syria, according to news accounts citing an unnamed Pentagon official.

On Friday, U.S. defense officials stated US F-22 Raptors flew within a mile of two Syrian Su-24 fighter jets and “encouraged” them to leave. The Raptors were there to protect US Spec Ops forces on the ground and operating in the area. No weapons were fired, according to multiple sources.

Encourage is a very loose term. If you are only going to fly within a few miles of an enemy fighter aircraft— and not perform a full intercept—then the Raptors probably locked on to the Su-24’s with their APG-77 AESA radar.

A radar lock or even a “paint” would highlight to the Su-24 pilots via their radar warning receiver that an enemy aircraft was in an offensive position against them.

Having a superior aircraft on your tail in an offensive position would be what I would call discouraging. Not knowing the full rules of engagement for U.S. aircraft, this seems to be the most plausible method for “encouraging” Syrian aircraft to leave the area.

The close encounter comes only a day after two Syrian warplanes attacked Kurdish forces. U.S. special operations forces had to be withdrawn from their position because of the attack.

During that event, U.S. and coalition troops were on the ground near the bombing in their train, advise and assist role, according to Navy Capt. Jeff Davis, a Pentagon spokesman.

“The Syrian regime would be well advised not to do things that would place them at risk,” he said. “We do have the right of self-defense.”

The Kurds are a key U.S. ally in the Syrian conflict.