Russian officials have said that the inspectors were unable to reach Douma because they had not been cleared by the United Nations and because of USA -led strikes carried out on targets in Syria on Saturday prevented them.
The United States, Britain and France have accused the Assad government of using chemical weapons in a Damascus suburb on April 7th.
Two days after the missile strikes which he hailed as a well-executed military operation, President Donald Trump still wants to bring U.S. troops home, the White House said on Monday. The OPCW has yet to disclose whether it has begun an on-site inspection. "Therefore allegations of this toward Russian Federation are groundless", Kremlin spokesman Dmitry Peskov said.
Organisation for the Prohibition of Chemical Weapons (OPCW) Director General Ahmet Uzumcu speaks during a news conference in The Hague, Netherlands, October 9, 2013.
Now, it is under the control of the Syrian government and Russian military.
The three countries consulted and collaborated on an assault in which more than a 100 missiles, reportedly targeting specific sites, were launched into Syria after the government was accused of a chemical attack.
Syrian flags flew in Douma on Monday, security forces stood on street corners and Russian military police patrolled the streets.
At least 40 people were killed in the Douma attack.
Doctors at the hospital where suspected victims were treated told reporters on the tour that none of the patients that night had suffered chemical weapons injuries - they were asphyxiated by dust and smoke in a bombardment. Syrian air defense systems intercepted 71 cruise missiles and air-surface missiles fired by the Western coalition, the Russian Defense Ministry said, adding that none of its own air defense units were involved in repelling the attack.
Medical aid groups and the White Helmets rescue organization have said such statements - already aired on state television in recent days - were made under duress.
The OPCW monitored the process and declared the Syrian government no longer possessed chemical weapons in 2014, before contradicting that assertion when it confirmed sarin gas was used in the northern Syrian city of Khan Sheikhoun last April.
Noah Smith, a journalist who writes for the New York Times and the UK's Guardian, discusses the suspected chemical attack in Douma, Syria and other summit developments..
But she will be questioned over why she did not seek parliamentary approval for the action, a decision that she and her ministers say was driven by the need to act quickly.
"After Assad's forces entered the area, they looted all houses, even the inhabited houses", said Humam Husari, a former Douma resident.