UPDATE 1500 GMT: Iran has provided cover for its ally by insisting that there is no evidence of a chemical attack on the East Ghouta area near Damascus

The Supreme Leader’s top aide, Ali Akbar Velayati, who toured East Ghouta and saw Bashar al-Assad last week, proclaimed on Sunday that the Iranian delegation saw nothing indicating a chemical assault.

Velayati said the accusation of the regime’s involvement was merely a pretext for aggression.

UPDATE 1430 GMT: The UN Security Council will meet on Monday to discuss a US-UK-French resolution for elimination of the Assad regime’s covert chemical stocks, and an independent investigation into chemical attacks.

Under the resolutoin, the Organisation for the Prohibition of Chemical Weapons will report within 30 days whether the Assad regime has refused to fully disclose chemical weapons despite a 2013 mandate — after the regime’s sarin attacks near Damascus that killed more than 1,400 people — for their removal.

UPDATE 1310 GMT: The opposition site Nedaa Syria, citing local sources, says Russian military police have taken “three to five” doctors, who refused to leave the city of Douma, to the al-Khatib Investigations Branch for interrogation.

The sources claim Russia offered to “resolve the situation” of the doctors, with no further questioning, in exchange for denying a chemical assault on Douma on April 7 if they are interviewed by the inspectors of the Organization for the Prohibition of Chemical Weapons.

If the doctors refuse, they will be arrested, the sources said.

One of the doctors who was taken, featured in a video from Russian State outlet Sputnik:

UPDATE 1300 GMT: Trying to show defiance of the airstrikes, the regime is circulating a video with extracts of Bashar al-Assad’s comments to Iranian President Hassan Rouhani on Saturday.

The US has warned that it will carry out further airstrikes if the Assad regime again resorts to chemical attacks in Syria’s conflict.

Nikki Haley, the US Ambassador to the UN, said Saturday at an emergency session of the Security Council:

If the Syrian regime uses this poisonous gas again, the United States is locked and loaded. When our President draws a red line, our president enforces the red line.

The US, UK, and France struck three Assad regime military complexes on Saturday: the Syrian Scientific Studies and Research Centre in the Damascus suburb of Barzeh; the Him Shinshar Chemical Weapons Storage Facility, 20 km (12.5 miles) west of Homs; and the Him Shinshar Chemical Weapons Bunker Facility, about 7 km (4 miles) from the storage facility. There were also claims some of the 105 missiles hit bases and depots used by elite army divisions in southern Damascus.

Haley said the three countries “acted not as revenge” but to “deter the future use of chemical weapons by holding the Syrian regime responsible for its atrocities against humanity”.

Russian Ambassador Vassily Nebenzia, still denying the chemical attacks by Moscow’s ally, called on the Security Council to condemn the US-UK-France strikes: “Today is not the day to shirk your responsibilities. The whole world is looking at you. Take a principled stand.”

But a Russian motion of condemnation was supported only by China and Bolivia. Eight countries voted No, and four abstained.

Bashar al-Ja’afari, the Assad regime’s ambassador, noted that the Organization for the Prohibition of Chemical Weapons had finally reached Douma in East Ghouta, hit by two regime chemical attacks on April 7 as part of an attempt to force surrender.

“My government will, of course, provide every support to this delegation for it to carry out its mission successfully,” Ja’afari said.

He did not note that the OPCW has been blocked by Russia for assigning responsibility for the attacks with chlorine and a stronger agent, which local doctors have assessed as an organophosphate.

Meanwhile, the head of the opposition High Negotiations Committee, Nasr al-Hariri, called for action to stop conventional as well as chemical assaults:

All attacks against Syrian civilians by the Assad regime and its allies must be stopped, whether these are launched with the use of chemical or conventional weapons. The number of Syrian civilians who were killed by barrel bombs, cluster munitions, rockets and other weapons is many times the number of those who were killed in chemical weapons attacks.

The Assad regime may not use sarin again, but it will not hesitate to use the weapons that the international community has allowed it to use, such as barrel bombs, cluster munitions, rockets, and toxic chlorine in small quantities.