Chlorine has legitimate industrial and other civilian uses, so it is not banned by the Chemical Weapons Convention.
"Last year the focus was on the delivery", Pentagon spokesperson Dana White said on Saturday.
They said Saturday's strikes may however lead to limited flare-ups on the ground, between these big players' respective proxies, including attacks against the US-backed Kurdish forces in northeastern Syria. Nedher Hammoud, 48, claimed to have seen missiles "being shot down like flies".
General Joseph F Dunford said the first target was a facility located in the greater Damascus area "for the research, development, production and testing of chemical and biological warfare technology".
May - who appeared to leave the door open to more strikes if the Assad regime repeated the used of chemical weapons - repeatedly dodged questions on whether she would seek some form of retrospective vote in parliament, saying only that she would address parliament on Monday, and take MPs' questions. Without going into specifics, they said there is no doubt based on a variety data from the ongoing analyses.
The draft, which sought to condemn the strikes as a violation of global law and the U.N. Charter, received only three votes in favor from the 15 council members.
And he thanked the United Kingdom and France "for their wisdom and the power of their fine military".
The allies also acted because of concerns that Russian and Syrian forces may already have tried to clean up important evidence in Douma, where more than 40 people died in last weekend's attack, the officials said.
President Bashar Assad's government denies responsibility.
The strikes as conducted last night instill no fear nor uncertainty on the part of the Syrian regime. Nor did they target intelligence capabilities, logistics sites, or other enablers of Syrian military chemical weapons efforts.
Russian guns were silent during the attack, the Pentagon revealed at a press briefing Saturday.
The US, France and Britain defended their military action as legal during the Security Council meeting. "Russia, however, can not claim to be a responsible member of the worldwide community while failing to condemn the use of chemical weapons and failing to take any action to prevent their use".
USA officials said they acted to defend allies attacked by the Syrian government as both rival forces raced toward Raqqa city, at the time the de facto capital of the IS militants.
The Russian ambassador to the UN Vassily Nebenzia, meanwhile, said Washington had embarked on an "illegal military venture".
Moscow's envoy said the three powers acted before allowing the fact-finding mission from the Organization for the Prohibition of Chemical Weapons, a watchdog group, to carry out its investigation.
"We specifically identified these targets to mitigate the risk of Russian forces being involved", Dunford told reporters, adding the USA military advised Russia of airspace that would be used in the strike but did not "pre-notify them". McKenzie says the strike will set Syria's chemical program back for years.
General Sergei Rudskoi told reporters in the Russian capital that two sites linked to Syria's chemical weapons program that were targeted were partly destroyed though they have always been out of use and had no personnel or equipment, he said.
President Trump's advisers have apparently convinced him to leave US forces in Syria for a little while longer to battle the Islamic State.