Against
RUSSIA: Unsurprisingly, the main ally of Syrian President Bashar al-Assad was robust in its opposition to the strike.
The strikes were an "aggression against a sovereign state in violation of international norms," the Kremlin said in a statement.
The action has inflicted "considerable damage" to already "lamentable" US-Russia ties, it added.
As a first practical response, Moscow said it would "halt" its deal with the US to avoid clashes in Syrian airspace.
Russia's military said the Syrian forces' air defences will be boosted following the US strike.
"To protect Syria's most sensitive infrastructure, a complex of measures will be implemented in the near future to strengthen and improve the effectiveness of the Syrian armed forces' air defence system," said spokesman Igor Konashenkov.
Russia also called for an urgent UN Security Council meeting following the strikes.
SYRIA: The Syrian government said it would redouble its efforts against rebel groups after the US strike which it called "foolish and irresponsible".
"What America did is nothing but foolish and irresponsible behaviour, which only reveals its short-sightedness and political and military blindness to reality," President Bashar al-Assad's office said in a statement.
Syrian army spokesman on US attack
IRAN: The Iranian regime, another Syrian ally, "strongly condemned" the strike, just as it condemned "all unilateral military action".
It said the US action was taken under the "pretext" of the chemical strike.
For
NATO: Syria is to blame for the US missile strikes NATO head Jens Stoltenberg said.
"The Syrian regime bears the full responsibility for this development," Stoltenberg said in a statement.
"Any use of chemical weapons is unacceptable, cannot go unanswered, and those responsible must be held accountable," he added.
EUROPEAN UNION: EU President Donald Tusk said in a tweet that the "US strikes show needed resolve against barbaric chemical attacks. EU will work with the US to end brutality in Syria."
Experts analyse Syrian attack aftermath
FRANCE/GERMANY: In a joint statement, President Francois Hollande and Chancellor Angela Merkel said Assad bore "sole responsibility" for the US strike following the suspected chemical attack.
BRITAIN: The close American ally said it "fully supported" the strikes, judging them an "appropriate response to the barbaric chemical weapons attack". It said the strikes were "intended to deter further attacks."
SPAIN: The Spanish government called the US action "a measured and proportionate answer to the use by the Syrian army of chemical weapons against the civilian population."
Pentagon footage of Tomahawk missile launch
TURKEY: NATO ally Turkey, which is a key player in the Syria conflict and has endured choppy relations with Washington recently, welcomed the strikes as "positive" but said that more action was needed.
"I want to say that I welcome this concrete step as positive," said Turkish President Recep Tayyip Erdogan, a longtime foe of President Bashar al-Assad.
"I don't see this as enough... the time has come for steps for a serious result to protect the oppressed Syrian people," he added.
Turkey called for a no-fly zone in Syria in the wake of the US strike.
And foreign Minister Mevlut Cavusoglu repeated Ankara's call for Assad to be removed from power, stressing: "This regime should be ousted from leading Syria at once."
SAUDI ARABIA: A foreign ministry official hailed US President Donald Trump as "courageous" for taking action when "the international community has failed to put a halt to the regime's actions."
ISRAEL: Prime Minister Benjamin Netanyahu said Israel "fully supports" the "strong and clear message" sent by the air strikes.
He added that the message should "resonate not only in Damascus, but in Tehran, Pyongyang and elsewhere."
JAPAN: Prime Minister Shinzo Abe said that Japan "supports the US government's resolve that it will never tolerate the spread and use of chemical weapons."
SYRIAN REBELS: A leading Syrian rebel group said one strike was "not enough", adding that there were "26 airbases that target civilians."
CANADA: Prime Minister Justin Trudeau said Canada supports the strike.
"Canada fully supports the United States' limited and focused action to degrade the Assad regime's ability to launch chemical weapons attacks against innocent civilians, including many children," he said in a statement.
ITALY: "Italy understands the reasons for the US military action, proportionate in its duration and methods," said Italy's Foreign Minister Angelino Alfano, who called for renewed US-Russia dialogue and international engagement to bring about regime change in Syria.
Others
CHINA: Beijing offered a nuanced reaction, saying it was "urgent" to avoid "further deterioration of the situation." A foreign ministry spokeswoman added: "We oppose use of chemical weapons by any country, organisation or individual in any circumstance, for any purpose."
UNITED NATIONS: UN Secretary-General Antonio Guterres urged restraint and said there was "no other way to solve the conflict than through a political solution."
"Mindful of the risk of escalation, I appeal for restraint to avoid any acts that could deepen the suffering of the Syrian people," he added in a statement.
