Over the weekend, the US shot down a Syrian Jet, Iran launched missiles into Syria, and the US killed large numbers of Syrian civilians in a raid in Raqqa.

With tensions escalating, Russia Warns US its Fighter Jets are Now Potential Targets in Syria.

The threat of direct Russian-American confrontation in Syria escalated on Monday after Moscow said it will treat any plane from the US-led coalition flying west of the Euphrates river as a potential target.

Russia said it was responding to US planes shooting down a Syrian air force jet on Sunday. The US said its planes had acted to defend US-backed forces seeking to capture the Islamic State capital of Raqqa in north-east Syria.

Russia's deputy foreign minister, Sergei Ryabkov, said the US strike "has to be seen as a continuation of America's line to disregard the norms of international law.

"What is this if not an act of aggression? It is, if you like, help to those terrorists that the US is fighting against, declaring they are carrying out an anti-terrorism policy."

The Russian ministry also said it would respond to the attack by suspending its communications channel with Washington, which is designed to prevent collisions and dangerous incidents in Syrian airspace.

The prime minister, Theresa May, intervened on Monday, urging Russia not to end the "deconfliction arrangements" since it increases the risk of an air fight breaking out inadvertently between Russian warplanes and US-led coalition warplanes.

Responding to Russian announcements, Marine Corps general Joseph Dunford, the chairman of the US Joint Chiefs of Staff, said the US would "work diplomatically and military in the coming hours to reestablish deconfliction".

The growing risk of a direct confrontation between the US and Russia follows a decision by US president Donald Trump to grant his military chiefs untrammelled control of he US military strategy in Syria.