Donald Trump has warned Russia and Iran there will be a "big price to pay" for backing the Syrian regime after a suspected chemical attack.

                                                                                                                                                                                                                    The US President condemned as "mindless" and "SICK" reports of at least 70 people being killed, and a further 500 injured, in an alleged chlorine gas attack in the city of Douma in eastern Ghouta.

Mr Trump and his French counterpart Emmanuel Macron also vowed a "strong, joint response" during a phone conversation, the White House said on Sunday evening.

It added that the regime of Syrian President Bashar al Assad "must be held accountable for its continued human rights abuses".

There has been no independent verification of the claims - made by the White Helmets rescue service and other opposition-linked medical relief groups - of a chemical attack.

However, the EU has said the "evidence points toward yet another chemical attack"                                                                                                                                                                                                                                                            Nine countries have called for an emergency meeting of the UN Security Council to discuss the reports: the UK, France, the US, Poland, Netherlands, Sweden, Kuwait, Peru and Ivory Coast. It is due to take place later.

The allegations have been denied by the Syrian government and Russia, with the latter separately calling for a Security Council meeting over "threats to international peace and security".                                                                                                                                                                                                                   Syrian media accused anti-Assad fighters in Douma of making "chemical attack fabrications" and added that allegations of toxic gas use are an "unconvincing broken record".

Iran branded the allegations as a "conspiracy" against Mr Assad, and warned that any US military intervention would "certainly complicate the situation" in Syria and the wider region.                                                                                                                                                                                                                                            The country's official IRNA news agency said the alleged attack had been condemned by the foreign ministry, which said in a statement: "Such allegations and accusations by the Americans and certain Western countries signal a new conspiracy against the Syrian government and people, and a pretext for military action."

It continued: "With the Syrian army having the upper hand on the ground against the armed terrorists, it would not be rational for it to use chemical weapons."

Mr Trump had earlier tweeted: "Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price...

"....to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"