At the press conference, May outlined the intelligence that led Britain to join the USA and France in launching more than 100 missiles against Syrian government targets overnight. A huge fire could be seen from a distance to the east.
The sounds of massive explosions rang out across Damascus just before dawn on Saturday, ushering in 45 minutes of explosions and the roar of warplanes, AFP's correspondent in the city said.
And Ahmad, a 25-year-old mechanic who had been displaced from Douma, told AFP the Western strikes were too little, too late.
President Emmanuel Macron said France had proof that the Syrian government had launched chlorine gas attacks in recent days, adding that his government would not tolerate "regimes that think everything is permitted", though he stopped short of saying whether France was planning military action.
"To Iran and to Russian Federation I ask: What kind of a nation wants to be associated with the mass murder of innocent men, women and children?" he said.
In a statement issued by the Kremlin, Putin said Moscow is calling an emergency meeting of the United Nations' Security Council over the strike launched by the U.S., Britain and France.
The missiles targeted three separate facilities linked to Syria's chemical weapons arsenal, including a research facility in Damascus, a chemical weapons storage facility in Homs - allegedly used to prepare the nerve agent sarin gas - and another nearby command post.
Jeremy Corbyn said the military action against Syria was "legally questionable" and makes real accountability for war crimes less likely. He added that Syria's air defenses were ineffective and that numerous more than 40 surface-to-air missiles fired by the Syrians were launched after the allied attack was over.
Syria's air defenses "were made in the USSR more than 30 years ago", the ministry said.
The Organisation for the Prohibition of Chemical Weapons (OPCW) has dispatched a fact-finding mission to the site of the alleged attack in Syria. The second target was a chemical weapons storage facility west of Homs.
But other advisors want to use the opportunity to convince Trump, who wants to pull U.S. forces out of Syria once the Islamic State jihadist group is defeated, to take a tough stance.
The ministry said it was an "attempt to block the exposure of their lies and fabrications".More news: Warriors dominate first half of Game 1
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Conservative commentator Ann Coulter also shared her opposition to the strike, retweeting a series of other conservative or right-wing figures who condemned the move and resurfacing Trump's own past tweets against military action in Syria.
Russian Federation on Saturday confirmed that it was calling an mergency session of the United Nations Security Council (UNSC) in the wake of the airstrikes launched by the US-led coalition in Syria.
Russia's US embassy released a statement warning that the airstrikes would "not be left without consequences".
Otherwise the attack did not draw a military response from Russian or Iranian forces operating in Syria, the Pentagon said.
"So there is no practicable alternative to the use of force to degrade and deter the use of chemical weapons by the Syrian regime, " May said. Assad's Barzah research and development center in the Damascus area was destroyed, the general said.
"Consequently, the United States is involved in this provocation", Sener said.
The Russian military said it hasn't engaged its air defense assets at its air and naval bases in Syria.
"The evil and the despicable attack left mothers and fathers, infants and children, thrashing in pain and gasping for air. They are crimes of a monster instead".
The US-led missile strikes in Syria appear to have been carefully calculated to minimise any further escalation in the Syrian war, while going as far as possible to prevent any further chemical attacks on civilians.
Angela Merkel said the US, Britain and France "took responsibility in this way as permanent members of the UN Security Council".
UN Secretary-General Antonio Guterres on Saturday called for restraint and for countries to avoid any acts that could escalate the situation in Syria after the United States, France and Britain carried out air strikes.