Inspectors from the Organization for the Prevention of Chemical Weapons (OPCW) were finally able to visit the two sites in Douma, Syria, where poison gas was allegedly deployed by dictator Bashar Assad.

The first site was accessed by inspectors on April 21, while the second was visited on Wednesday, April 25.

The attacks occurred on April 7, so two weeks elapsed before the first site was examined by the inspectors, and 18 days before the second was visited. A previous attempt to examine the sites on April 18 was canceled due to security concerns. U.S. and British officials accused the Syrians and their patrons in Russia of stalling the investigation so the sites could be “sanitized” of evidence.

A statement released on Wednesday said that samples were collected from the second site and returned to OPCW laboratories for analysis.

The statement also chastised Russia for trying to upstage the official Fact-Finding Mission (FFM) by organizing its own briefing on the Syrian chemical attack allegations:

The OPCW Technical Secretariat was informed by the Russian delegation to the OPCW that it will organise a organize for States Parties in The Hague on 26 April. The delegation would bring some Syrians to speak about the reported Douma incident.

In line with Director-General’s earlier requests to States Parties to share information on the Douma incident, the Secretariat advised the Russian delegation that these persons should be first interviewed by the FFM. It was also recommended that such a briefing take place once the FFM has completed its work.

Nevertheless, the Russian delegation stated that it would go ahead with the briefing and that its intention was not to interfere with the FFM’s work.

Britain and France condemned the Russian briefing in much stronger terms, calling it an “obscene masquerade” staged to protect a Syrian government that has “massacred and gassed its own people for the last seven years.”

On Tuesday, Syrian filmmaker Humam Husari denounced Russia for using footage from his 2016 film about a 2013 sarin gas attack near Damascus in a “very cheap and very tacky” attempt to make it look like the April 7 attack was faked.

“I think this is a cheap attempt by the Russians to deny the obvious, and I think this is very desperate,” said Husari.