"I think we dealt them a severe blow", Lt. Gen. Kenneth McKenzie, director of the Joint Chiefs of Staff, said at the Pentagon after the overnight bombing.
This time about twice the number of cruise missiles were launched by the United States in response to last Saturday's alleged chemical attack by Assad on the town of Douma just outside of Damascus, in which at least 40 people died and hundreds were sickened.
He said that the Syrian leader had launched a "savage" chemical weapons attack previously and again recently. "Thank you to France and the United Kingdom for their wisdom and the power of their fine Military", Trump tweeted.
"Could not have had a better result", he tweeted.
Trump's United Nations ambassador, Nikki Haley, said the president had not yet made a final decision, two days after he tweeted that Russian Federation should "get ready" because a missile attack "will be coming" at Moscow's chief Middle East ally.
In the biggest foreign military action so far against Syria's regime, Western officials said a barrage of cruise and air-to-land missiles hit targets near Damascus and in Homs province including a scientific research centre, storage facilities and a command post.
Syrian President Bashar al-Assad said Western strikes on government military installations Saturday only made him keener to fight back against his opponents, in comments published by his office.
Trump said the U.S. was prepared to sustain economic, diplomatic and military pressure on Assad until he ends what Trump called a criminal pattern of killing his own people with internationally banned chemical weapons.
"The attack took place after the colonial forces supporting terrorists realized they have lost control and got the feeling that they have lost credibility in front of their people and the world", Assad said.
The Syrian opposition, however, said the strikes would not change much in the country.
President Donald Trump has declared "Mission Accomplished" for a US-led allied missile attack on Syria's chemical weapons program, but the Pentagon says the pummelling of three chemical-related facilities left enough others intact to enable the Assad government to use banned weapons against civilians if it chooses.
Moscow may consider supplying S-300 surface-to-air missile systems to Syria and "other countries", Colonel-General Sergei Rudskoi told a televised briefing on Saturday.
Trump chastised Syria's two main allies, Russia and Iran, for their roles in supporting "murderous dictators", and noted that Russian President Vladimir Putin had guaranteed a 2013 worldwide agreement for Assad to get rid of all of his chemical weapons.
May said that Britain has "sought to use every possible diplomatic channel" to stop the regime of Syrian President Bashar Assad, "but our efforts have been repeatedly thwarted".
- Syrian state TV called the attacks a "blatant violation of global law and shows contempt for worldwide legitimacy". An AP reporter in Damascus says the attacks turned the sky orange. The United States responded with 58 missile strikes that destroyed 20 percent of the Syrian Air Force.
White says the strikes do not "represent a change in US policy or an attempt to depose the Syrian regime".
Syria had omitted to declare numerous activities of its Scientific Studies and Research Centre (SSRC), the report said.
Experts say Syrian military personnel are believed to have evacuated from major facilities ahead of the attack as the USA had warned of possible military action, minimizing damage and losses.