- US prepared to "sustain" strikes until Syrian regime stops using chemical agents - Trump
- May: 'We are acting together with our allies'
- French President Emmanuel Macron also confirmed his country's participation in the operation.
- US and allies launch strikes on Syria chemical weapons sites
The US, UK and France have bombed multiple government targets in Syria in an early morning operation targeting alleged chemical weapons sites.
The strikes are in response to a suspected chemical attack on the Syrian town of Douma last week.
Explosions hit the capital, Damascus, as well as two locations near the city of Homs, the Pentagon said.
Russia's ambassador to the US responded by saying the attack on its ally "will not be left without consequences".
"A combined operation with the armed forces of France and the United Kingdom is now underway," President Trump said in an address to the nation from the White House at about 21:00 local time (02:00 BST).
A 'one-time shot'
At a Pentagon briefing shortly afterwards, Gen Joseph Dunford listed three targets that had been struck:
A scientific research facility in Damascus, allegedly connected to the production chemical and biological weapons
A chemical weapons storage facility west of Homs
A chemical weapons equipment storage and an important command post, also near Homs
Syrian state television said government forces had shot down more than a dozen missiles.
US Secretary of Defence James Mattis told reporters there were no reports of US losses in the operation.
In his earlier address, President Trump had said: "We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents."
But Secretary Mattis said that "right now, this is a one-time shot". Gen Dunford confirmed the wave of strikes had ended.
UK strikes in Homs
Gen Dunford said the US had specifically identified targets that would "mitigate" the risk of Russian casualties. But the Pentagon said that Russia - which has forces on the ground in Syria in support of the government - had not been given advance notice of the targets.
Image Copyright @RusEmbUSA @RusEmbUSA
UK Prime Minister Theresa May confirmed British involvement, saying there was "no practicable alternative to the use of force".
But she also said the strikes were not about "regime change".
UK strikes carried out by four Tornado jets hit one of the targets mentioned by the Pentagon - a military site near the city of Homs which is believed to have housed precursor materials for chemical weapons, according to the UK ministry of defence.
"Dozens of men, women and children were massacred with chemical weapons," he said of the Douma incident a week ago - adding that "the red line had been crossed".