Australia says it is temporarily suspending its military air operations over Syria, after a warning from Russia that it would treat aircraft from the US-led coalition as potential targets.
The pause was a “precautionary measure”, the government said, without giving details.
Moscow’s warning came after the US shot down a Syrian military plane.
Russia also said it was halting communications with the US aimed at preventing such incidents.
Australia has deployed about 780 military personnel as part of the US-led coalition fighting so-called Islamic State (IS) in both Iraq and Syria.
The halt in operations comes as the coalition and the fighters it is supporting on the ground attempt to oust IS militants from the city of Raqqa, the de facto capital of the “caliphate” they proclaimed in 2014.
“Australian Defence Force protection is regularly reviewed in response to a range of potential threats,” the defence department said in a statement.
“ADF 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.”
Australia joined the US-led coalition in Syria in September 2015, but did not carry out any operations in the country between March and May this year, according to the defence department.
Its activities in Iraq, where it carried out 80 operations in May alone, will continue.
Australia’s decision to suspend air operations over Syria in the wake of Russia’s warning that it might target coalition aircraft is an indication of the concern among Washington’s allies, but is unlikely to have a significant impact upon the air campaign.
Australia has a small but highly capable contingent of six F/A-18 strike aircraft; a tanker; and an E-7A Wedgetail early warning aircraft, all based at Al Minhad in the United Arab Emirates. Most of the Australian strikes have been in Iraq, though its aircraft do also operate over Syria.
Australian commanders will reassess the situation in due course. The more fundamental question is what the Russian threat actually amounts to. Is it just rhetoric or does Moscow want to deny certain areas of Syrian airspace to US-led coalition aircraft?
With the assault on the de facto IS capital Raqqa just getting under way, the last thing the Pentagon needs is a stand-off with Moscow.
Russia warned on Monday that it would track coalition aircraft with missile systems and military aircraft, but it stopped short of openly saying it would shoot them down.
The move came after the US shot down a Syrian Su-22 which, the Pentagon said, had bombed US-backed fighters battling IS near the town of Tabqa in Raqqa province.
It was believed to be the first air-to-air kill of a manned aircraft by a US military jet since the Kosovo campaign in 1999.
But both Russia and Syria said the warplane was on a mission against IS about 40km (25 miles) south-west of Raqqa when it came under fire.
The Syrian army said the “flagrant attack” would have “dangerous repercussions”.
Russia also denied the US had used a communications channel before the Su-22 fighter bomber was shot down, as claimed by the US military.
In response, it said was ending a memorandum of co-operation with the coalition aimed at preventing air incidents and guaranteeing flight safety.