The F-15E Strike Eagle shot down the Shaheed-129 drone that was connected with Syrian government forces, the Pentagon said about the incident, according to USA Today.
Two days earlier, an American FA-18 shot down a Syrian SU-22 warplane that had dropped bombs near American-backed fighters combating the Islamic State.
On several occasions in recent weeks, warplanes of the US -led coalition have also struck pro-government forces to prevent them advancing from the Al Tanf garrison in southeastern Syria at a spot where the country's borders join Iraq and Jordan.More news: Obama readied USA for 'cyberwarfare' against Russian Federation after hearing of election interference
In response to the downing of the Syrian plane, Russian Federation warned that it would target any American and coalition planes that flew west of the Euphrates River.
Australia defence ministry said in a statement the suspension was "a precautionary measure to allow the coalition to assess the operational risk".
Australia is part of the coalition that began airstrikes against Islamic State targets in Syria in September 2014. The drone was observed in the same area where another UAV was shot down on June 8.
Meanwhile, US General Joseph Dunford, the chairman of the Joint Chiefs of Staff, said a day earlier that Washington was working to restore a "deconfliction" line with Moscow meant to avoid mid-air collisions over Syria.
Russia stressed it would in future be tracking the coalition's jets, not shooting them down, but added that "a threat for those jets may appear only if they take action that poses a threat to Russian aircraft".More news: Syria troops position themselves at heart of war on IS
The two latest shoot downs, in addition to the one on June 8, has raised questions over whether the U.S.is getting drawn into a war with Russian Federation or Syria, rather than just with ISIS. "When the armed UAV continued to advance on the Coalition position without diverting its course it was shot down", CENTCOM continued.
The Australian Defense Force's name for its effort to fight ISIS is Operation OKRA.
Tensions have also flared between USA forces and the Syrian regime further north, where the coalition is supporting an alliance of Kurdish and Arab fighters battling to oust IS from the city of Raqa.
Syrian and Iranian-backed ground forces also have been gathering in the desert region.
That incident followed two others involving U.S. fire against pro-regime forces on the ground as they came close to the garrison.More news: Ronaldo header gives Portugal 1-0 win over hosts Russia