The decision to strike, after days of deliberations, marked Trump's second order to attack Syria. "The United States of America will not allow the Assad regime to continue using chemical weapons".
The aim, she said, is "to see American troops come home, but we are not going to leave until we know we have accomplished those things".
The building was central to Bashar Al-Assad's chemical weapons program. USA officials said the Syrian military planes that dropped the chemicals had taken off from there. US officials said no one was hurt there.
Trump and European leaders had spoken of intervention earlier this week after a suspected chemical weapons attack in the former rebel stronghold of Douma last weekend, killed around 85 civilians.
USA envoy Haley also said that if Trump draws the red line, he enforces it and the U.S. will continue to sustain pressure on Syria.
Western powers blamed President Bashar al-Assad, but Syria and its ally Russian Federation categorically denied the claims and accused the West of "fabricating" the incident to justify military action. Putin added that Russian military experts who inspected Douma found no trace of the attack.More news: Justin Bieber punches man at Coachella party
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The Pentagon said the strike was created to degrade Syria's chemical weapons capability without killing civilians or foreign fighters.
McKenzie defended the attacks in response to questions about the proof that Assad had used chemical weapons on civilians.
■ April 6, 2017: In retaliation for a chemical weapons attack in northern Syria that killed almost 90 people, the USA fires 59 Tomahawk missiles at the government-controlled Shayrat air base in central Syria.
According to the Pentagon, 76 missiles hit the target near Damascus, 22 more rockets were fired at a warehouse west of Homs.
The vote reflected support for the airstrikes on Syrian chemical sites but it also demonstrated again the paralysis of the U.N.'s most powerful body in dealing with the Syria conflict. "This massacre was a significant escalation in a pattern of chemical weapons used by that very awful regime".
Lt. Gen. Kenneth McKenzie, the director of the Joint Chiefs of Staff at the Pentagon, says the USA -led airstrikes against Syria has been "a very serious blow". "This was not about interfering in a civil war and it was not about regime change".
The statement said "a significant number" of missiles were shot down by Syrian air defences.