The United States had fired nearly 60 Tomahawk missiles at a military air field in Syria, the first direct military action Washington has taken against Syrian government forces in the six-year-old conflict.
Washington said the strikes on Friday severely damaged or destroyed Syrian aircraft and support infrastructure and equipment at the airfield.
US President Donald Trump said he ordered the strikes against Shayrat air base in Homs province, saying it is believed that a suspected gas attack on a town in Idlib province had been launched from there. Trump said he acted in America's "vital national security interest".
World leaders and countries across the world were quick to react to the news.
Saudi Arabia said it "fully supports" the strikes, adding that it was a "courageous decision" by President Donald Trump in response to the alleged use of chemical weapons against civilians in the town of Khan Sheikhoun, in northwestern Syria
"A responsible source at the foreign ministry expressed the Kingdom of Saudi Arabia's full support for the American military operations on military targets in Syria, which came as a response to the Syrian regime's use of chemical weapons against innocent civilians," a statement carried by state news agency SPA said.
The statement said it holds the government of Syrian President Bashar al-Assad responsible for the deaths of dozens of civilians in in Khan Sheikhoun.
In contrast, Iran, an ally of Assad in the conflict, said it strongly condemned the missile strikes against the
Shayrat air base.
"Iran strongly condemns any such unilateral strikes ... such measures will strengthen terrorists in Syria ... and it will complicate the situation in Syria and the region," ISNA news agency quoted Foreign Ministry spokesman Bahram Qasemi as saying.
Israeli Prime Minister Benjamin Netanyahu said on Friday he supports the "strong and clear message" sent by the US strikes.
The Israeli military said it had been informed in advance of the attack.
"In both word and action, President (Donald) Trump sent a strong and clear message today that the use and spread of chemical weapons will not be tolerated," a statement from Netanyahu's office said.
"Israel fully supports President Trump's decision and hopes that this message of resolve in the face of the Assad regime's horrific actions will resonate not only in Damascus, but in Tehran, Pyongyang and elsewhere."
Britain said the US action was an appropriate response to the "barbaric chemical weapons attack" launched by the Syrian government, according to a spokesman for Prime Minister Theresa May.
Australian Prime Minister Malcolm Turnbull also weighed in, saying that he supported the strike, calling it a "proportionate and calibrated response".
In a televised statement, he also called on Russia to play its part in bringing peace to Syria.
Meanwhile, Bolivia has requested the UN Security Council hold closed-door consultations on Friday about the missile strikes, a senior Security Council diplomat said.