A US F-15E fighter jet shot down a Syrian regime drone on Monday near At Tanf, Syria, the third downing of a pro-regime aircraft this month, CNN reported. The downing of the drone comes a day after a US jet shot down a regime aircraft that was engaging a fleeing ISIS convoy, according to the Syrian government.

An armed Shaheed-129 UAV “displayed hostile intent and advanced on Coalition forces” at 12:30 am local time on Tuesday, the coalition said in a statement. The drone was observed in the same area where another UAV was shot down on June 8.

Here’s CNN:

"The drone was downed just outside the 55 kilometer de-confliction zone, according to the officials. It was an Iranian-made Shahed 129 and was thought to be armed and in firing range of US troops. One official said that the drone was shot down because it was 'assessed to be a threat.' That drone was shot down after it dropped one of several weapons it was carrying near a position where coalition personnel are training and advising partner ground forces in the fight against ISIS."

According to Fox News, this is the second time the US has shot down an Iranian drone in less than a month. It also marks the fifth time since late May the U.S. military has bombed pro-Syrian forces in southern Syria.

Connecticut Sen. Chris Murphy described the attack as “a dangerous escalation" of tensions between the US and the main backers of the Syrian regime, Russia and Iran.

Murphy told CNN that if the US doesn't stop the attacks, the situation could escalate into an armed conflict between the two sides, who both claim to be fighting ISIS.

“I think we’re getting closer and closer to open conflict between Iran and Russia and the American public need to know that we are moving very fast towards what could be another war in the Middle East – something Donald Trump promised he wouldn’t do when he ran for office.”

The US's actions could also prompt its coalition partners to withdraw from Syria, wary of being drawn deeper into an armed conflict with Iran and Russia. On Tuesday, Australia said it would temporarily suspend fights in the conflict zone as a "precautionary measure" after Russia said it would withdraw from an air-safety agreement in retaliation for Sunday's downing of the Syrian aircraft.

On the same day that the drone was shot down by US forces, an armed Russian fighter jet buzzed a U.S. Air Force reconnaissance aircraft in the Baltic Sea, two U.S. officials told Fox News.

In the latest in a long series of close encounters, Fox News reports the Russian Su-27 jet had missiles under its wings and approached the U.S. Air Force RC-135 recon jet "rapidly," coming within five feet of the American aircraft, the officials said.

Once alongside, the Russian jet was “provocative” in its flight maneuvers and flying “erratically,” according to another official.