US Secretary of State Rex Tillerson, in a stern address before his crucial Moscow visit, has thanked Australia and other allies for supporting last week's Syrian airbase missile strike and predicted Syrian leader Bashar al-Assad's reign is coming to an end.
Mr Tillerson also called out Russia for failing to live up to its obligations to ensure the Syrian regime eradicated its chemical weapons and urged Moscow abandon support for the Syrian dictator.
"The US is grateful for the statements of all of our partners who have expressed support for our timely and proportional response," Mr Tillerson told reporters on Tuesday in Italy at a G7 foreign minister's meeting before flying to Russia.
"As events shift, the United States will continue to evaluate its strategic options and opportunities to de-escalate violence across Syria."
Australian Prime Minister Malcolm Turnbull described US President Donald Trump's order to send 59 Tomahawk missiles into the Syrian airbase as a "swift response to a shocking crime".
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US allies in Asia, Europe and the Middle East, including Britain, France, Japan, Saudi Arabia and Qatar, also publicly supported the missile strikes.
"It is our policy for a unified Syria that is governed by the people of Syria," Mr Tillerson said.
"I think it is clear to all of us that the reign of the Assad family is coming to an end."
