A picture taken during a Syrian army-organized tour on April 20 shows a man walking past ruined buildings in the Eastern Ghouta town of Douma on the outskirts of Damascus.
CNN  — 

Experts from the world’s chemical weapons watchdog hope to exhume the bodies of victims of an alleged chemical attack in Syria in order to take samples, the body’s chief has said.

At least 48 people died in the suspected chemical attack in Douma, the last rebel-held town in Eastern Ghouta, on April 7.

A fact-finding team from the Organisation for the Prohibition of Chemical Weapons finally collected samples from the site in Douma on April 21, after waiting days for access. The delay raised concerns that any chemicals potentially used could have degraded before inspectors reached the site or that evidence could have been manipulated.

The OPCW is now seeking samples from the remains of those killed in the attack, Director-General Ahmet Uzumcu told the Financial Times.

“From the bodies already buried we are looking for ways to exhume if possible and take some biomedical samples,” Uzumcu said.

A spokeswoman for the OPCW told CNN that the body is “continuing to explore all avenues for collecting evidence” into the attack, adding that it was “premature to speculate” on when a report into what happened would be published.

UK officials say about 75 people were killed in the attack on the rebel stronghold on the outskirts of Damascus. US officials have said they believe chlorine and sarin gas were dropped there.

Both Syria and its most powerful ally, Russia, deny a chemical attack took place.

The US, the UK and France have blamed Syrian President Bashar al-Assad’s regime for the assault and together carried out airstrikes in response.

Russia has claimed the April 7 attack was “faked,” or even “staged” with the help of British intelligence agencies. Britain denies the allegation.