Russian officials and President Trump have USA have exchanged heated rhetoric since Trump began talk of a US response to the alleged chemical attack throughout the past week. As he spoke, explosions rocked Damascus.
Defence Minister Florence Parly said cruise missiles had been fired, in coordination with the United States and Britain.
Three civilians were wounded in Homs after "several" missiles were intercepted by Syrian air defense systems, Syrian state TV said.
May said Britain and its allies had sought to use every diplomatic means to stop the use of chemical weapons, but had been repeatedly thwarted, citing a Russian veto of an independent investigation into the Douma attack at the U.N. Security Council this week.
The Latest: A global chemical warfare watchdog group says its fact-finding mission to Syria will go ahead even after the US -led airstrikes.
"These are crimes of a monster", said Trump, adding that Bashar al-Assad's "recent attack... are a direct result of Russia's failure..."
The situation in Damascus and other towns and cities in Syria is calm now, Rudskoi said. Another eyewitness say that Barzah district of Damascus had been hit in the strikes.
The first target, they said, was a research center involved in the development and production of chemical and biological weapons.
The targets included research centers in Damascus believed to have produced chemical weapons.
A senior official in a regional alliance that backs Damascus told Reuters the Syrian government and its allies had "absorbed" the attack, and that targeted sites were evacuated days ago thanks to a warning from Russian Federation. Mattis said no additional attacks were planned, though Trump earlier suggested the strikes could last longer.
The chairman of the worldwide affairs committee of Russia's upper house of parliament, Konstantin Kosachev, said the strikes were a violation of worldwide law and probably created to prevent investigators from the global chemical weapons watchdog from doing their work.
The presence of Russian troops and air defenses in Syria were among numerous complications weighing on Trump, who must also consider the dangers to roughly 2,000 American troops in the country if Russia were to retaliate for USA strikes.
An Israeli official told CNN that the strikes enforced the red line drawn by President Trump a year ago.
Russian Federation had issued a warning on Tuesday saying that any United States missiles fired at Syria over the assault on a rebel enclave would be shot down and the launch sites targeted. The war has sucked in a number of actors - including Russia, Iran and Iran-backed Lebanese militia Hezbollah on the side of Assad.
In a direct address to the two countries, he asked, "What kind of a nation wants to be associated with the mass murder of innocent men and women and children?"
"A new round of strikes will most likely impose costs and degrade the regime's capability to launch such (chemical weapons) attacks by damaging Assad's remaining air force", she wrote.
And it's not like chemical weapons are completely unheard of in Syria: Assad's forces have used them over 200 times since the beginning of the civil war, according to a tally by chemical weapons expert Rebecca Hersman.
U.S. aircraft including B-1 bombers and ships were used in the attack, United States defence officials said.
Let's be clear: These limited strikes nearly certainly did not destroy the Syrian government's entire chemical weapons stockpile, let alone seriously set back its ability to fight anti-government rebels. At the time, the Pentagon claimed that a fifth of Syria's operational aircraft were either damaged or destroyed.
The strikes seemed unlikely to have much impact on the balance of power in Syria's seven-year-old civil war, in which Assad's government has steadily gained the upper hand against armed opponents since Russian Federation intervened in 2015.
Jean-Yves Le Drian told reporters Saturday that the joint military operation in Syria is legitimate, limited and proportionate.
The report said that for now France did not have chemical samples from the attack site analysed by its own laboratories yet.