Syrian activists on Saturday (April 4th) renewed their call for the Syrian regime to be held to account for the killing of Syrian civilians in the course of its military operations on the third anniversary of a deadly gas attack on Khan Sheikhun.

The April 4th, 2017 attack, in which sarin gas projectiles were fired into the opposition-held town in Idlib province, killed 83 people, according to the UN.

The Syrian Observatory for Human Rights gave a death toll of 87, including more than 30 children.

Activists staged demonstrations in numerous areas of Idlib on the third anniversary of the attack, Idlib activist Haisam al-Idlibi told Diyaruna.

In addition to the dead, he noted, 500 others suffered from the inhalation of poisonous gases, which caused symptoms such as breathing problems, vomiting, fainting and foaming at the mouth.

"The demonstrators renewed their call for the Syrian regime to be held accountable for carrying out the attack and other attacks of a similar nature that also have been documented," al-Idlibi said.

He noted that UN investigators had determined that sarin gas, which is internationally banned, had been used in the attack.

Al-Idlibi said the demonstrators also blamed Russia for its role in supporting the Syrian regime -- taking part in the military operations and attempting to cover up the regime's responsibility for committing these crimes.

Syrian activists have documented 221 chemical attacks carried out against civilians from 2012 through 2019 by regime forces and their allies, he said.

They claim these resulted in the death of 1,460 named victims, including 185 children and 252 women, and the injury of about 10,000 others.

Khan Sheikhun is now under the control of the Syrian regime and its allies, al-Idlibi said, noting that opposition forces withdrew from it some time ago, after fierce fighting in rural Idlib.

This kept civilians from going to visit the graves of those killed on the anniversary of the 2017 attack, he said, adding that it did not keep them from remembering the dead or from calling for the regime's accountability.