The White Helmets, a rescue group operating in Syria say at least 70 people have died after toxic gas was dropped on Douma, the last rebel-held town in Syria's Eastern Ghouta.

The rescuers reported that most of the fatalities were women and children. The White Helmets tweeted graphic images showing scores of bodies in a basement. It said the death toll is likely to rise. There has been no independent verification of the reports.

Rescuers reported that an entire family had suffocated to death as they hid in their cellar, trying to seek shelter from air raids and barrel bombs. Raed al-Saleh, head of the White Helmets, told Al Jazeera, that chlorine gas, as well as an unidentified but stronger gas, were dropped on Douma.

The Douma Media Centre, a pro-opposition group, posted images on social media of people being treated by medics, and of what appeared to be dead bodies, including many women and children.

Rescue workers also posted videos of people appearing to show symptoms consistent with a gas attack. Some appeared to have white foam around their mouths and noses.

Douma is the last rebel-held town in Syria's Eastern Ghouta region, and is under siege from government forces. Pro-government forces and their allies on Friday launched a fierce air and ground offensive on Douma. The Syrian government has recaptured nearly all of eastern Ghouta from rebels in an offensive that began in February, leaving just Douma in the hands of an insurgent group, Jaish al-Islam. Syria's state news agency SANA said the heavy bombardment, which shattered 10 days of calm, and in contravention to UN's call for halt to violence, was in response to shelling by Jaish al-Islam, the armed group in control of Douma, on residential areas in Damascus.

The U.S. state department said it is monitoring the "very disturbing" reports, and that Russia - which is fighting alongside the Syrian government - should be held responsible if deadly chemicals had been used. "The regime's history of using chemical weapons against its own people in not in dispute," said the state department. "Russia ultimately bears responsibility for the brutal targeting of countless Syrians with chemical weapons," it ended.

Reports suggest that more than 100,000 civilians remain trapped in Douma and unlikely to receive any assistance as the city had suffered devastating damage during the latest government assault.

(The above story first appeared on LatestLY on Apr 08, 2018 09:51 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).