State TV says chemical weapons watchdog arrives in Douma as France and the US question the purpose of the mission.

Chemical weapons inspectors have entered the Syrian town of Douma to probe an alleged poison gas attack, according to the state-run SANA news agency.

The delegation from the Organisation for the Prohibition of Chemical Weapons (OPCW) entered the town near the capital, Damascus, along with the Syrian health minister on Tuesday, a source close to the government told Germany’s DPA news agency.

“What we understand is that they are going to inspect and investigate the site of that alleged chemical weapons attack,” said Al Jazeera’s Zeina Khodr, reporting from Beirut in neighbouring Lebanon.

“They are going to take samples and talk to witnesses, doctors and people who were there,” she added.

The reported toxic gas attack on Douma on April 7 sparked joint missile strikes by the United States, France and Britain on Syrian military installations.

The punitive attacks early on Saturday were launched before a fact-finding team from the OPCW was able to enter Douma and begin its fieldwork.

Earlier on Tuesday, the mission had appeared in question.

During an emergency meeting on Monday at the OPCW’s headquarters in The Hague, Western diplomats accused the Syrian government and its Russian ally of blocking the team, which arrived in Damascus on Saturday.

Russia denied the claims, saying parts of Douma still needed to be de-mined and said the watchdog’s inspectors would enter on Wednesday.

Yet, France and the US appeared to question the purpose of such a mission, warning that any incriminating evidence had likely been removed by now.

“It is highly likely that evidence and essential elements disappear from the site, which is completely controlled by the Russian and Syrian armies,” the French foreign ministry said.

Ken Ward, US ambassador to the OPCW, claimed on Monday that the Russians had already visited the site and “may have tampered with it”.

Syrian and Russian forces gained control over Douma on Saturday when rebels withdrew from the town, hours after the end of the Western countries’ attacks.

Al Jazeera’s Khodr said that even if the OPCW finds that the chemical weapons attack happened, there would be no new punitive strikes.

“At the end of the day, we are not expecting any retaliation because the US and its allies already carried out retaliatory strikes,” she said.

“They were not waiting for the OPCW findings, and they made it clear that they will strike again if another chemical weapons attack happens.”