DAMASCUS, Syria — At least 50 civilians were being treated Saturday following a suspected poison gas attack by Syrian rebel groups on the government-held city of Aleppo in the country’s north, according to reports in Syrian state media.

Most of those admitted to hospitals had breathing problems and blurred vision, doctors told state TV. One doctor said two were in critical condition, including a child. State TV showed footage of medical professionals treating men and women on hospital beds.

There was a stench of gas in Aleppo after projectiles were fired, said Rami Abdurrahman, the head of Britain-based Syrian Observatory for Human Rights.

Rebel commanders and opposition figures discredited the government reports, denying they lobbed gas into Aleppo and accusing Damascus of seeking to undermine an existing cease-fire and efforts to kickstart political talks. Earlier Saturday, government shelling of a rebel-held area in neighboring Idlib province killed at least seven civilians.

In Aleppo, local governor Hussein Diab visited the injured at the hospital. He told state TV that 41 people had been admitted and accused rebels of using poisonous gas in the missiles they lobbed at the Aleppo neighborhood.

Health official Haj Taha later said the number of injured was up to 50, adding that symptoms suggest the gas used was chlorine. Further tests are needed, he said.

The projectiles landed in the al-Khalidiya neighborhood, and wind caused gas to spread, Aleppo police chief Essam al-Shali told state TV. State TV later said the gas affected two other areas in the city. There were no deaths, al-Shali said.

One patient said a foul smell filled the air after projectiles were lobbed.

“There are often missiles on the city but this is the first time we smelled such a smell,” the patient said without giving his name.