Iran's president Hassan Rouhani has said his country will apply all efforts to prevent military action against the Tehran-backed regime of Syrian president Bashar Assad, Iranian state TV is reporting.

The report said the remarks came late last night during a phone conversation between Mr Rouhani and his Russian counterpart Vladimir Putin.

He was quoted as saying "military action will have a big amount of costs for the region" and "it is necessary to apply all efforts to prevent it".

According to the report, he said both Iran and Russia would work to prevent any military action against Syria and called such action an "open violation" of international laws.

While condemning chemical weapons, Mr Rouhani was quoted as saying that "early judgment can be dangerous, before clarification" of allegations that Syria used such weapons.