Russia is getting ahead of the inevitable and defending Syria against any potential U.S. drone strikes, say four U.S. officials.

According to NBC News:

The Russians began jamming some smaller U.S. drones several weeks ago, the officials said, after a series of suspected chemical weapons attacks on civilians in rebel-held eastern Ghouta. The Russian military was concerned the U.S. military would retaliate for the attacks and began jamming the GPS systems of drones operating in the area, the officials explained.

Jamming, which means blocking or scrambling a drone’s reception of a signal from a GPS satellite, can be uncomplicated, according to Dr. Todd Humphreys, the director of the Radionavigation Laboratory at the University of Texas at Austin.

“GPS receivers in most drones can be fairly easily jammed,” he said.

This isn’t a new thing with Russia, in their never-ending quest to be the most unscrupulous of world players.

Four years ago, U.S. analysts saw this blocking capability at work in eastern Ukraine, after the invasion of Crimea. Russia’s military jammed drones at that time, having what is described as a “significant impact” on United Nations surveillance drones, attempting to monitor the region and gather information.

Malfunctions and crashes are very possible results of the jamming.

The Defense Department will not say whether the jamming is causing drones to crash, citing operational security. “The U.S. military maintains sufficient countermeasures and protections to ensure the safety of our manned and unmanned aircraft, our forces and the missions they support,” said Pentagon spokesman Eric Pahon.

Russia has jumped ahead of any expected hit on Syria, given Bashar al-Assad’s latest chemical weapon attack on the rebel-held Douma in Eastern Ghouta, Syria. Trump had strong words, following the attack, and drew his own “red line” towards both Assad, and Russia, for their compliance.

Still, the Russian strategy of jamming U.S. drones is having some effect.

The officials said the equipment being used was developed by the Russian military and is very sophisticated, proving effective even against some encrypted signals and anti-jamming receivers. The drones impacted so far are smaller surveillance aircraft, as opposed to the larger Predators and Reapers that often operate in combat environments and can be armed.

Dr. Humphreys further commented on the outcome of any jamming efforts:

“They are a little less hostile looking than a kinetic bullet but sometimes the effect can be just as damaging,” he said. “It’s like shooting at them with radio waves instead of bullets.”

This is just another phase in this quagmire that is Syria.