She also said that no country should use chemical weapons and go unpunished. The military said there were three targets: the Barzah chemical weapons research and development site in the Damascus area, a chemical weapons storage facility near Homs and a chemical weapons "bunker" a few miles from the second target.
It is barred from having, storing or using nerve agents, and while it is permitted to possess chlorine for civilian uses, is banned from using that chemical as a weapon.
Syria has continued to deny any chemical weapons were used.
Secretary of Defense James Mattis called the strikes a "one time shot" and said that they were aimed at Syrian government's chemical weapons infrastructure.
In a statement, Australian Prime Minister Malcolm Turnbull said Australia supported the strikes, which sent "an unequivocal message to the Assad regime and its backers, Russian Federation and Iran, that the use of chemical weapons will not be tolerated".
Moscow condemned the Western states for refusing to wait for OPCW's findings before attacking.
Both Russia and Iran, Assad's other main ally, have warned his enemies against military action in recent days, underlining their commitment to the Syrian government they have armed and supported through years of conflict.
"Ten days ago President Trump wanted the United States of America to withdraw from Syria".
Russian Federation has military forces, including air defenses, in several areas of Syria to support Assad in his long war against anti-government rebels.
In Damascus, Assad told a group of visiting Russian lawmakers that the Western missile strikes were an act of aggression, Russian news agencies reported.
But while Russia slammed the missile attack rhetorically, it signaled that the strike had not crossed the threshold that would bring Russian retaliation.
Hours later, the Russian Embassy in Damascus said no Russians were known to have been hurt in the overnight airstrike. "Putin is now saving Assad with the money of Russian retirees".
Mr Lavrov said Russian experts had inspected the site of the claimed attack and found no trace of chemical weapons.
British Prime Minister Theresa May describes the attack as neither "about intervening in a civil war" nor "about regime change" but a limited and targeted strike that "does not further escalate tensions in the region" and does everything possible to prevent civilian casualties.