(CNSNews.com) – Nine days after a suspected chemical weapons attack in Douma, Syria, the Organization for the Prohibition of Chemical Weapons had as of Monday still not been allowed access to the site – despite the insistence of the Russians and Assad regime that they are cooperating fully.

Russian officials have, however, visited the site, and on Monday the U.S. ambassador to the OPCW, Kenneth Ward, voiced concern that they may have “tampered” with evidence there.

“It is our understanding the Russian Federation may have visited the attack site,” Ward told a meeting of the OPCW executive council in The Hague.

“We are concerned they may have tampered with it with the intent of thwarting the efforts of the OPCW fact-finding mission [FFM] to conduct an effective investigation. This raises serious questions about the ability of the FFM to do its job.”

At the same meeting, OPCW director-general Ahmet Uzumcu confirmed that the FFM, which eventually arrived in Damascus on Saturday, had not yet been permitted to visit Douma.

“The team has not yet deployed to Douma,” Uzumcu told the closed-door meeting, according to a statement released by the OPCW.

“The Syrian and the Russian officials who participated in the preparatory meetings in Damascus have informed the FFM team that there were still pending security issues to be worked out before any deployment could take place.”

The regime did offer to bring “22 witnesses” to Damascus to be interviewed by the OPCW team, Uzumcu added.

“I hope that all necessary arrangements will be made through the UNDSS to allow the team to deploy to Douma as soon as possible,” he said. (The UNDSS, or U.N. Department of Safety and Security, oversees security clearances and travel advisories for U.N. personnel.)

At the meeting, Britain’s ambassador to the OPCW, Peter Wilson, accused Russia of a long record of obstructionism relating to chemical weapons use by its ally in Syria.

“Since 2016, Russia has sought to undermine every OPCW investigation into allegations of regime chemical weapons use,” he said. “Yet again, Russia is spreading conspiracy theories and misinformation designed to undermine the integrity of the OPCW’s fact finding mission.”

Wilson also recalled that Russia last November used its U.N. Security Council veto to shut down a joint OPCW-U.N. task force mandated to establish whether chemical agents have been used in Syria, and if so, by whom.

Weeks earlier, the joint mechanism had found the Assad regime guilty of using sarin in the April 4, 2017 attack in Khan Sheikhun. That was the incident that prompted the first U.S. missile strike, which targeted a Syrian airbase days after the attack.

In Moscow, Deputy Foreign Minister Sergei Ryabkov denied accusations that Russia was hampering the OPCW team’s mission. He blamed delays in its trip to Douma on the airstrikes – “the illegal, unlawful military action” – launched by the U.S., Britain and France on Friday.

A still from a White Helmets video shows children suffering the effects of a suspected chemical attack in Douma on Saturday, April 7, 2018. (Screen capture: White Helmets)

‘Blocked from entering’

On Saturday, Pentagon spokeswoman Dana White said during a briefing on the strikes that the “OPCW and others have been blocked from entering Ghouta and Douma … because of the Assad regime.”

“This is a lie,” responded Russian foreign ministry spokeswoman Maria Zakharova later that day. “Damascus approved the arrival of the OPCW experts.”

A similar protestation came from Foreign Minister Sergei Lavrov: “It is not true,” the TASS state news agency quoted him as saying in Moscow.

“The Syrian government was ready to issue visas immediately on the [Syria-Lebanon] border, without any additional delay,” he said. The Pentagon did not charge that the OPCW team had been unable to enter Syria, but noted it had not been able to visit the alleged attack site.

In the fall of 2013, Moscow brokered an agreement for President Bashar al-Assad to surrender his “declared” chemical weapons stockpile, after more than 1,400 Syrians were killed in a chemical attack blamed on the regime.

The agreement was widely seen as a Russian maneuver to avert punitive airstrikes pledged – but ultimately never carried out – by President Obama, after Assad violated his 2012 “red line” on chemical weapons use.

The regime duly handed over the “declared” stockpile, and then-Secretary of State John Kerry said the following year he had “struck a deal [with the Russians] where we got 100 percent of the chemical weapons out.”

Since then, the regime has been accused of using chemical weapons, including sarin and chlorine gas, on a number of occasions, most recently on April 7 in Douma. It has denied doing so.

Russia has backed it up in the denials. Last week Moscow charged that the Douma incident was “staged” by the volunteer rescue organization known as the White Helmets.

On Monday in The Hague, it presented a different theory, alleging that the attack was a “provocation” by the British intelligence agencies, “perhaps with the participation of their senior allies from Washington.”