

This photo, provided Tuesday, April 4, by the activist Idlib Media Center, shows dead children after a suspected chemical attack in the rebel-held city of Khan Sheikhoun, Syria. Dozens of people were killed, according to multiple activist groups.

A man carries a child at a makeshift hospital in Khan Sheikhoun. Activists have blamed the Syrian regime for the attack. In an apparent reference to the attack, two state-run Syrian media outlets reported that there was an explosion at a "rebel poison gas factory" in the countryside of Idlib province. The government has denied using chemical weapons in the past.

A child's body is seen in Khan Sheikhoun.

In this photo provided by the Idlib Media Center, doctors treat a child after the suspected attack.

A baby's dead body is covered. Many of the casualties came as a result of asphyxiation, local doctors say.

A dead baby is seen in the aftermath of the attack. "I've never seen anything like it, beyond description," said Fares al-Jundi, a doctor who spoke with CNN. He lives in a nearby village and rushed to the hospital after the airstrikes.

Al-Jundi described how whole families were killed: They died of asphyxiation, and foam covered their mouths. Many died suddenly. "I believe this horrible memory will stay with me for the rest of my life," al-Jundi said.

An unconscious Syrian child receives treatment at a hospital in Khan Sheikhoun.

This photo provided by the Idlib Media Center shows victims of the suspected attack.

Civil defense workers try to reduce the effects of toxic gas as they carry out search-and-rescue missions in Khan Sheikhoun.