Senator: US at risk of military conflict with Russia, Iran in Syria

Both Syria's Su-22 and the US's F/A-18E Super Hornet are updated versions of 1970s aircraft, but Russian Federation and the USA both have much more advanced systems to bring to bear.

As a result of the threat, Australia said on Tuesday it would suspend its military campaign.

"Australian defense force personnel are closely monitoring the air situation in Syria, and a decision on the resumption of ADF air operations in Syria will be made in due course", a spokesman for Australia's defense department told the country's ABC news outlet.

Gen. Joseph Dunford, the chairman of the Joint Chiefs of Staff, insisted that the "deconfliction channel" between the US military and its Russian counterpart, established eight months ago, is still operating.

Murphy's remarks came two days after a U.S. Navy fighter jet shot down a Syrian warplane for the first time, prompting Russian Federation to issue a threat against American airborne assets over Syrian airspace. "If you're going to ramp up military activity against Assad, you are also going in against Iran and Russian Federation".

The Australians, who have six F-18F Super Hornets flying strike missions as part of the US -led coalition out of the UAE, have also decided that this is a problem and have suspended their participation in air strikes altogether.

But then a Syrian Su-22 popped up laden with bombs.

The official said the U.S. pilot saw the Syrian pilot eject and saw a parachute deploy, but the USA believes the pilot would have landed in ISIS-controlled territory in Syria.

US -backed Syrian militias closed in on Islamic State's Syrian stronghold of Raqqa on Wednesday, taking territory on the south bank of the Euphrates River with the aim of encircling the city, a militia spokesman told Reuters.

Tensions between the United States and the Syrian regime, including its Iranian-backed allies, have escalated in recent months.

Immediately after the Syrian Su-22 fighter jet dropped its bombs, two American F/A-18E Super Hornets, flying from the George H.W. Bush aircraft carrier, engaged, firing a AIM-9 Sidewinder - a short-range air-to-air missile - at the Syrian plane from about half a mile away, two United States officials told CNN.

"The Coalition's mission is to defeat ISIS in Iraq and Syria", U.S. Marine Maj. "The Coalition presence in Syria addresses the imminent threat ISIS in Syria poses globally".

The incident occurred in the same vicinity as previous conflicts with pro-regime forces, near the combat outpost in At-Tanf, where a contingent of USA and coalition advisers are supporting a force to fight the Islamic State, also known as ISIS.