Syria's UN ambassador told the United Nations Security Council Tuesday that a UN security team traveled to the town of Douma, outside the capital Damascus, to ascertain whether it was safe for global chemical weapons experts to visit the site of a suspected chemical weapons attack last week that killed dozens.

Bashar Ja'afari said if the team decides "the situation is sound," the fact-finding mission from the international chemical weapons watchdog — Organization for the Prohibition of Chemical Weapons — will start work there Wednesday.

Earlier on Tuesday, Syrian state media falsely reported that members of the world's chemical weapons watchdog had entered Douma.

The news was denied by western countries. The US State Department said it did not believe the OPCW had entered the site of the April 7 attack. A diplomatic source told Reuters news agency that the experts had not entered Douma.

The West has criticized the delay in allowing access to the site to the investigators, who arrived in Syria last week.

The French Foreign Ministry said they believed it was "highly likely that evidence and essential elements disappeared from the site, which is completely controlled by the Russian and Syrian armies."

The US Ambassador to the OPCW, Ken Ward, said Monday that he believed the Russians "may have tampered with" the site.

Expert to DW: OPCW can detect tampering

Alastair Hay, a professor of environmental toxicology at the University of Leeds, spoke to DW about the prodecure investigators use to try and ascertain what chemicals were at play in the attack.

According to Hay, investigators will ideally want to talk to victims and doctors to get a picture of the symptoms they were experiencing after the attack and establish a timeline. 

They'll also try to take samples from the blast site, as the chemical used will be blasted into the surrounding surfaces and the weapons used may still be there. If possible, gathering samples from deceased victims will be "very valuable" since the substances could still be in their blood and organs.

While Hay agreed that it was likely "Russians or others may very well be trying to clean up things. Throwing dust everywhere and trying to make it look natural," OPCW observers can usually be able to tell if a site has been tampered with.

Hay said the weapon looked to be composed of an irritant like chlorine mixed with a nerve agent: "It certainly looks like some chemical attack from the social media footage I have seen."

Putin phones Merkel over Western strikes

Images of dead children and civilians from the alleged attack shocked the world, and prompted the US, France and UK to launch airstrikes against chemical weapons facilities in Syria.

Syria, along with its allies Russia and Iran, criticized the Western powers for striking without proof of an attack. However, Western leaders have claimed that there was eyewitness testimony from both civilians and NGOs, such as the World Health Organization (WHO), that corroborated the chemical attack. UK Prime Minister Theresa May also told parliament on Monday that neither Syrian rebels nor "Islamic State" terrorists had the means of carrying out such an attack.

Russia has previously accused Britain of staging the incident, mirroring its back-and-forth with London over the poisoning of Sergei and Yulia Skripal. The Kremlin said on Tuesday that President Vladimir Putin had telephoned German Chancellor Angela Merkel, who supported the Western strikes but did not participate in them.

Putin reportedly stressed to Merkel that he believed the US, UK and France had broken international law and hampered the Syrian peace process.

ap, es/aw (AP, AFP, dpa)

Additional reporting by Rebecca Staudenmaier