US-led coalition forces launched a coordinated attack on Syria in an operation tagetted to end the “criminal” regime of Bashar al-Assad which has been accused of gassing innocents in an alleged chemical attack.

US President Donald Trump announced on Friday the launch of the operation, saying that the chemical attack had marked a “significant escalation.”

“A short time ago, I ordered the United States armed forces to launch precision strikes on targets associated with the chemical weapons capabilities of Syrian dictator Bashar al-Assad,” Trump said in a primetime televised address to the nation.

“A combined operation with the armed forces of France and the United Kingdom is now under way. We thank them both. This massacre was a significant escalation in a pattern of chemical weapons use by that very terrible regime.

British PM Theresa May said she had authorised British armed forces “to conduct co-ordinated and targeted strikes to degrade the Syrian regime’s chemical weapons capability.”

French President Emmanuel Macron confirmed that France had joined the US and Britain in an ongoing operation against Syria with strikes to target “the capacities of the Syrian regime to produce and use chemical weapons”.

The coordinated strike on Friday marked the second time in a year that Trump has used force against Assad, who US officials believe has continued to test the West’s willingness to accept gruesome chemical attacks, The Washington Post reported.

“The purpose of our action tonight is to establish a strong deterrent,” Trump said, against the production and use of chemical weapons, describing the issue as vital to national security.

Trump added that the US is prepared “to sustain this response” until its aims are met.

Trump asked both Russia and Iran, backers of Assad, “kind of nation (they) want to be associated” with mass murder and suggested that someday the US might be able to “get along” with both if they change their policies.

Social media users posted videos of the attack. Missile strikes were seen across the well-lit city of Damascus, which then plunged into darkness.

Another video of airstrikes in Damascus #Syria pic.twitter.com/plUtB8AFuh

— Arturas Kerelis (@arturaskerelis) April 14, 2018

Return defense fire in Damascus #Syria pic.twitter.com/LtdEr15pqM

— Arturas Kerelis (@arturaskerelis) April 14, 2018

Reports indicate that the Barzah district of Damascus, which is the location of a Syrian scientific research centre, may have been hit by the strikes.

(With inputs from agencies.)