"It's been 33yrs since chemical attack in Sardasht," Iranian Foreign Ministry wrote on its Twitter account.
"We did & will never forget the support & complicity of US/Europe in the horrible attack by Saddam," it added.
"We did & will never forget the UNSC silence on this heinous crime. We rebuild whatever they destroyed," Iran’s Foreign Ministry stressed.
Tens of thousands of Iranians were killed and wounded by chemical weapons during the 1980-1988 Iraqi imposed war on Iran. Around 100,000 Iranians are still living with the effects, which include long-term respiratory problems, eye and skin problems as well as immune system disorders, psychological disorders, genetic disorders, and probably cancers.
Sardasht is a city in Northwestern Iran. According to the 2006 census, its population was 37,000. It lies in the West Azarbaijan province. It was the first city in which civilians were attacked with chemical weapons by former Iraqi dictator, Saddam Hussein during the imposed Iraqi war on Iran.
The population of Sardasht is Kurdish. The city is also known for the many villages around it and their reliability on the city's market.
On June 28, 1987, Iraqi aircraft dropped what Iranian authorities believed to be mustard gas bombs on Sardasht, in two separate bombing runs on four residential areas.
Sardasht was the first town in the world to be gassed. Out of a population of 20,000, 25% are still suffering severe illnesses from the attacks.