President Trump said on Friday he had ordered strikes on Syrian targets, seeking to punish President Bashar al-Assad for a suspected chemical attack near Damascus that killed more than 40 people.
Mr. Trump said Britain and France had joined the United States in the strikes.
The strikes risked pulling the United States deeper into the complex, multi-sided war in Syria from which Mr. Trump only last week said he wanted to withdraw. They also raised the possibility of confrontation with Russia and Iran, both of which have military forces in Syria to support Mr. Assad.