Updated 12.15pm 

The US decision to bomb a Syrian airbase it believes was the launchpad for a deadly chemical attack sparked a reaction in the capitals of many world powers. 

Here are their initial reactions so far: 

United Kingdom: Britain said it fully backed the move, with a government spokesman saying "the UK Government fully supports the US action, which we believe was an appropriate response to the barbaric chemical weapons attack launched by the Syrian regime, and is intended to deter further attacks."

Russia: Russian news agencies reported that president Vladimir Putin believes the US missile strikes broke international law and have seriously hurt US-Russia relations.

The Russian leader, a staunch ally of Syrian President Bashar al-Assad, regarded the US action as "aggression against a sovereign nation" on a "made-up pretext" and as a cynical attempt to distract the world from civilian deaths in Iraq, Dmitry Peskov, Putin's spokesman, was cited as saying.

War continues to tear through Syria. Photo: Reuters

Foreign Minister Sergei Lavrov told a news conference the bombing was "an act of aggression, on an absolutely made-up pretext"  and likened it to the 2003 invasion of Iraq. 

China: China has adopted the stance of honest broker, appealing for calm and a diplomatic resolution to the conflict. 

A Foreign Ministry spokesman said the country hoped "relevant parties stay calm, exercise restraint and avoid doing anything that might raise tensions."

"The latest developments in Syria again speak to the urgent need for a political settlement to resolve the Syria issue," Hua Chunying told reporters at a regular briefing.

"We call on all relevant parties to resolutely stick to promoting a political settlement and not abandon efforts to find a political settlement."

France & Germany: In a joint statement, French president Francois Hollande and German chancellor Angela Merkel said the two countries would continue to push for a UN-backed peace settlement. 

In Paris, Mr Hollande confirmed French backing for the US action, saying France had been seeking U.S. missile strikes in 2013 after a previous chemical attack.

Assad bore "full responsibility for this development," Hollande said in a joint statement with Germany from the Elysee after speaking with Chancellor Angela Merkel. 

French Foreign Minister Jean-Marc Ayrault said France had been informed by the United States before the strikes and that Russia should use this "warning" to push for a political solution to the Syrian conflict.

"The United States has started clarifying its position because over the last few days we heard one thing and then another," Mr Ayrault said.

"A signal was sent, because yet again a red line was crossed by Assad," Ayrault said. "The use of chemical weapons is appalling and should be punished because it is a war crime."

NATO: NATO Secretary-General Jens Stoltenberg said that Syrian President Bashar al-Assad "bears full responsibility" for the US airstrikes.

"Any use of chemical weapons is unacceptable, cannot go unanswered, and those responsible must be held accountable," said Stoltenberg, who was informed by the US defence minister that strikes would go ahead.