One week after a suspected sarin gas attack on the last rebel-held town in Ghouta left scores of Syrian civilians dead, President Donald Trump announced on Friday that the United States had conducted a retaliatory strike against Syrian military interests. “A combined operation with the armed forces of France and the United Kingdom is underway,” Trump said. The president had met with top military and national security advisers earlier in the day. Trump had wavered on the possibility of military action in response to the attack, at one point warning Syrian leader Bashar al-Assad and Russian President Vladimir Putin that “missiles are coming,” then later saying that an attack “could be be very soon or not so soon at all!” The strike is the second such retaliatory action in response to suspected use of chemical weapons by Assad; in April of last year, Trump responded to a similar attack by launching more than 50 Tomahawk missiles at an airbase near Homs. Russia, which has backed Assad’s regime, had threatened to shoot down any American missiles detected in Syrian airspace.