European Council president Donald Tusk said the European Union would stand with its allies “on the side of justice”.
He added: “Strikes by US, France and UK make it clear the Syrian regime, together with Russia and Iran, cannot continue this human tragedy, at least not without cost.”
Backing the strikes Nato Secretary General Jens Stoltenberg said it would “reduce the regime’s ability to further attack the people of Syria with chemical weapons”.
He added: “Nato has consistently condemned Syria’s continued use of chemical weapons as a clear breach of international norms and agreements. Their use is unacceptable, and those responsible must be held accountable.”
“The innocent Syrian people should have been defended long ago.”
Israel said the attack sent an important signal to the “axis of evil” of Iran, Syria and the militant group Hezbollah.
Yoav Gallant, a member of Prime Minister Benjamin Netanyahu’s security cabinet, said: “The use of chemical weapons crosses a red line that humanity can no longer tolerate.”
But Russian president Vladimir Putin condemned the Syria strikes as an “act of aggression” that would have a “destructive” influence on international relations.
He also claimed the military action made the humanitarian catastrophe worse and hurt civilians. “Russia in the most serious way condemns the attack on Syria where Russian military servicemen help the legitimate government to fight terrorism,” he said.
Syrian state media called the attack a “flagrant violation of international law”, while Iran’s supreme leader Ayatollah Ali Khamenei called it a “crime”.
He added: “I clearly declare the president of the US, the president of France and the British prime minister are criminals.
“They will not benefit [from the attack] as they went to Iraq, Syria and Afghanistan in the past years and committed such crimes and did not gain any benefits.”