The World Health Organization (WHO) has demanded “unhindered access” to Douma in Syria, to check reports from its partners that 500 people have been affected by a chemical attack there.

The Syrian government denies being behind any chemical attack.

The US has threatened a “forceful” response to reports of an attack but Russia has called this a “pretext” to attack its ally, Syria.

The WHO said more than 70 people had reportedly died after the attack.

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