And then on Friday night, the countries hit three targets - including one on the outskirts of Damascus - all related to Syria's chemical weapons program: a research center, a storage facility, and an equipment facility and command post.
"Everything over the previous 48 hours has indicated toward some sort of de-escalation, that the attacks might happen in the future".
All 12, it said, had been downed using Soviet-made air defense systems. No casualties have been reported. It said it was calling an emergency session of the United Nations Security Council. "This time, our allies and we have struck harder", said Defense Secretary James Mattis.
Damascus, with key allies Russian Federation and Iran, have lambasted reports of the suspected gas attack as bogus.
Bashar Jaafari, permanent Representative of the Syrian Arab Republic to the United Nations, Russian Ambassador to the United Nations Vasily Nebenzya and Sacha Llorenty, Permanent Representative of Bolivia to the United Nations talk at the end of the emergency United Nations Security Council meeting on Syria at the U.N. headquarters in NY, U.S., April 14, 2018.
More than half a million people have been killed in the Syrian conflict, which has been ongoing for over seven years. "There's some left, but we dealt them a severe blow".
Vice President Mike Pence said the operation "degraded and crippled" and "significantly eroded" the Assad government's ability to use chemical weapons. Trump signaled last month that he wanted a complete withdrawal of US forces in Syria, taking many observers by surprise.
As Trump was making his White House address, large explosions were heard in the capital Damascus, with footages showing missiles streaking over the night sky in Syria. "The United States will be a partner and a friend".
- "The United States will be a partner and a friend but the fate of the region lies in the hands of its own people".
In his speech, Trump warned Russian Federation and Iran not to stand by their ally in Damascus.
"I ask what kind of a nation wants to be associated with the mass murder of innocent men, women and children", Trump said.
The military action is not about intervening in Syria's civil war or changing its government, she said. "They are crimes of a monster instead". The attacks had continued, culminating in Saturday's attack in Douma. Russia vetoed a USA text, while two Russian-drafted resolutions failed to get a minimum nine votes to pass.
"The attempts of Washington, London and Paris to undermine the activities of the OPCW mission are systematic".
More details will continue to emerge in upcoming days.