The United States and European allies launched strikes against Syrian targets, President Trump announced on Friday, 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, which he said were underway.
“These are not the actions of a man. They are crimes of a monster instead,” Mr. Trump, in a televised nighttime address from the White House Diplomatic Room, said of the Syrian attacks last weekend that he blamed on Mr. Assad.
He said the strikes of precision weapons sought to deter the production, spread and use of chemical weapons, which he called “a vital national security interest of the United States.”