Meanwhile, French President Emmanuel Macron says France has proof the Syrian government used chemical weapons. He made the comment in an interview on Thursday. Macron added he was communicating with Trump, and that they "will have decisions to take in due course". Other European countries have given mixed responses to the prospect of taking action against the Syrian government. Our correspondent in Paris, Elena Casas, has more details.

ELENA CASAS PARIS "French President Macron is going further than the US since he says that France does have proof that chemical weapon strike was carried out by Assad government last week. He now has that challenge that he needs to work out what the media response would look like."

EMMANUEL MACRON FRENCH PRESIDENT "We have proof that last week, now nearly ten days ago, that chemical weapons were used, at least chlorine, and that they were used by Assad regime."

In an interview on Thursday, he said he has talked to Donald Trump several times this week, and the US and France would work on joint plan that would be carried out in due course. He said that the action plan would be aimed to take out the Assad government's chemical infrastructure, and that would require very good intelligence to hit the labs that might manufacture these chemicals.

ELENA CASAS PARIS "We've seen mixed responses from other European countries. It's also politically difficult for Theresa May to order an air strike without holding full parliamentary vote on it which can't come before Monday. ELENA CASAS, CGTN, PARIS."