Assad regime forces dropped a barrel bomb containing poisonous chemicals on civilians in eastern Ghouta, killing at least 70 and injuring more than 500 people, reports said Saturday.

"The Assad regime and its allies carry on with their crimes," the opposition group's military spokesman Hamza Birqdar told al-Hadath TV.

Cases of suffocation between the civilians in residential neighborhood in the city #Douma after it was targeted by poison gas "Chlorine". @SyriaCivilDefe teams are working to inspect the place and transfer the injured to medical centers. pic.twitter.com/07FrrKns31

— The White Helmets (@SyriaCivilDef) April 7, 2018

The Syrian Observatory for Human Rights, a war monitor based in Britain, reported 11 cases of symptoms of suffocation in the city, including five children, following strikes by Assad regime warplanes. It did not say what agents may have been used in the attacks.

UPDATE — 40 civilians killed, hundreds injured in Assad regime's chemical attack in opposition-held eastern Ghouta's Douma, local sources say https://t.co/FqFGxVYgxV pic.twitter.com/Tq5gnRJmJV

— DAILY SABAH (@DailySabah) April 7, 2018

Meanwhile, local sources said at least 70 people were killed and 1000 more were injured from the attacks.

The death toll is expected to rise to "well over 100," the charity Union of Medical Care and Relief Organizations (UOSSM) said Sunday.

"Many of the victims were women and children and experienced symptoms consistent with inhaling toxic gas," it said in a statement.

"Some of the symptoms victims experienced include cyanosis; foaming of the mouth; cornea irritation; and the strong odor of a chlorine-like substance.

"The death toll is expected to rise to well over 100 victims as Syrian Civil Defense teams have experienced extreme difficulty reaching victims due to the continued bombardment on Douma," it continued.

The disturbing photos coming from Douma also showed a number of civilians, including children, suffering breathing difficulties and other symptoms of indicative of exposure to chemical compounds.

Neither the opposition group nor the Observatory mentioned any deaths.

Syrian state media denied launching chemical attacks as soon as the reports began circulating.

The regime launched a fierce air and ground assault on Douma, the last rebel-held town in eastern Ghouta, on Friday, killing 48 people in the last 24 hours alone.

State TV showed thick clouds of smoke rising from Douma, where Jaish al-Islam is holding out after insurgents in other parts of eastern Ghouta accepted offers of safe passage to opposition-held areas in the north of the country.