EU ministers point to Assad and Russia on Syria gas attack

The attack came one day ahead of Wednesday's large donor conference on Syria in Brussels and has rattled leaders in their efforts to find a peaceful solution to the six-year-old raging war.

"I know it sounds surreal, especially today, but if you want peace you have to start building peace," said the EU's foreign policy chief Federica Mogherini in light of the attacks.

Both the UK and France have called for an emergency Security Council meeting at the United Nations in New York. The two countries are veto-holding permanent members of the council.

British and French foreign ministers, Boris Johnson and Jean-Marc Ayrault, told reporters in Brussels that the resolution aims to condemn the chemical attack and calls for an immediate international investigation.

"I don't think anybody could possibly, reasonably oppose such a resolution in all conscience," Johnson said.

Johnson and Ayrault say all the evidence behind the attack points to the regime under strongman president Bashar al-Assad, with Ayrault pointing out that the planes used in the raid were "Russian-made".

Images emerging from the attack show children choking and foaming at the mouth.

Hundreds of thousands have been killed in the war, with around 5 million Syrians fleeing their homes to seek refuge outside the country.

"He [Assad] is responsible for the vast majority of that butcher's bill and you have to go a long way back in history to find a tyrant who had stayed in office in such circumstances," said Johnson.

Johnson also appeared to echo comments by US president Donald Trump, who said Barack Obama should have upheld the "red line" promise of acting in Syria, following a similar gas attack in 2013 in Ghouta.

"I am afraid that the people of Syria are living today with the consequences of that decision," said Johnson.

Germany wants answers

The blame on Assad may implicate the regime's staunchest ally and military supporter in Moscow.

But Russia denies any involvement and says the chemicals were released after a rebel depot was bombed.

The view has been roundly rejected, with Germany's foreign minister, Sigmar Gabriel, saying Russia has to clarify its role.

"Russia is responsible for clarifying matters, clarifying matters as soon as possible," he said.

The UN is also seeking answers.

A UN investigative body, the Organisation for the Prohibition of Chemical Weapons, has been tasked to launch a probe.

"We need to have accountability based on the results of that investigation," said the UN secretary general, Antonio Guterres.