The United States has fired more than 50 missiles at a Syrian airbase following orders from President Donald Trump. The escalation was in response to the chemical weapon attack earlier this week, which killed more than 80 civilians, including at least 30 Syrian children. The attack has been widely blamed on Syrian President Bashar al-Assad's regime. This is what we know so far:
What has just happened?
The United States has launched more than 50 Tomahawk missiles at the al-Shayrat military airfield near Homs, an air base that is under the control of the Assad government.
A chemical attack was launched from this airfield earlier this week on the town of Khan Sheikhoun in Syria, in which at least 80 people were killed, including some 30 children.
The Syrian government denied responsibility for the chemical attack. The Russian government said chemicals leaked when the Syrian government conducted an air strike on a rebel-held chemical weapons depot.
What is the latest Trump has said on the strikes?
In a press conference about midday on Friday Sydney time, Trump said the strike was "to prevent and deter the spread of deadly chemical weapons".
He said there was no dispute Syria was behind the chemical attack.
"Years of previous attempts at changing Assad's behaviour have all failed," he said. He called on other nations to end terrorism.
"We ask for God's wisdom as we face this challenge," he said.
Has anyone been killed in the missile strike?
Syrian state television says the strikes "led to losses". CNN reported there were Russian personnel at the base at the time of the strike. It is not known if they were injured.
What is Australia's position?
It is being reported that Trump received support from nations including Australia before launching the attack.
Australian Prime Minister Malcolm Turnbull has not yet commented on the US's response, but he has previously called for a strong response to the deadly chemical attack.
Opposition leader Bill Shorten supports the strikes. "We support the US sending a strong signal that these gas attacks should have never occurred - and they should never occur again," he said.
How will Russia respond?
It will certainly raise the risk of confrontation with Assad's main military supporters, Russia and Iran.
A senior military official said there were no Russian planes at the Shayrat airbase and Russian military officials were informed ahead of the strike.
Just before the attack, Russia's deputy UN envoy, Vladimir Safronkov, warned of "negative consequences" if the United States carried out military strikes on Syria over the deadly toxic gas attack. His government accused Trump of being "too hasty" in his response.
Neither country's leader has yet issued a statement on the strikes.
How are people reacting?
The attack was described as "American aggression" by Syrian state TV.
A Pentagon statement said "he strike was a proportional response to Assad's heinous act". . "Shayrat Airfield was used to store chemical weapons," it said.
Republican Senator Tom Cotton applauded Trump's military action. "I commend President Trump for taking swift, decisive action against Bashar al-Assad's outlaw regime."
Fellow Republican Bob Corker, who is the chairman of the United States Senate Committee on Foreign Relations, also welcomed Trump's "decisive action".
"It is critical that Assad knows he will no longer enjoy impunity for his horrific crimes against his own citizens, and the proportional step was appropriate."
What happens next?
The UN Security Council may convene another emergency meeting. The world is expecting Russia and Iran to make a statement.
How did the United States initially respond to the chemical attack?
On Thursday, the United States signalled it could take a more aggressive response to the chemical attack..
When asked if the attack on a Syrian hospital crossed a "red line", Trump said "it crossed a lot of lines". "That crosses many, many lines, beyond red lines," he said.
At a sitting of the United Nations Security Council an hour earlier, US Ambassador Nikki Haley stood up at her desk to show diplomats photos of dying children and accused Russia, which backs Syria, of pushing a false narrative blaming rebel forces for the attack.
