Russian authorities say a team of inspectors sent by the Organization for the Prohibition of Chemical Weapons, also known as OPCW, will visit the site of the attack on Wednesday.
The experts would be entering the site eleven days after the suspected posion gas attack killed at least forty and injured more than hundred people on April 7th.
They will be looking to see whether any chemical weapons were actually used.
An OPCW official said the team arrived in Damascus over the weekend, but they were denied access to the site by Russian and Syrian officals who told them that there were pending security issues to be resolved before they could enter.
The U.S. envoy to the OPCW, Kenneth Ward, told Reuters that there are concerns about the inspection being delayed saying that evidence of the chemical attack might have already been tampered with by Moscow.
Russia has denied that.
Foreign minister Sergei Lavrov said Moscow has not tampered with the site, and that there was no chemical attack in the first place.
Kremlin spokesman Dmitry Peskov also added that Russia does not intend to hinder the probe.
He called America's recent missile strikes on Syrian government facilities illegal and suggested they may have slowed down the investigation.
Washington carried out massive air strikes on three alleged chemical weapons facilities in Syria along with Britain and France this past Saturday, and said they would launch more missiles if Damascus uses chemical weapons again.
Cho Sung-min, arirang news.