The attack, the deadliest in Iran in recent years, occurred in the city of Pisheen, near the border with Pakistan in Sistan-Baluchestan province, Fars and ILNA news agencies said.
"A man wearing an explosives vest blew himself up inside the meeting," the official IRNA news agency said.
Iran's state broadcaster said the attack occurred at around 8am (1530 AEDT) in front of a local gymansium.
Fars said the strike took place when officers from the Guards were preparing to stage a meeting between local leaders of Shiite and Sunni communities. Some local tribal heads were also among the slain, media reports said.
"In this terrorist act, General Nur-Ali Shushtari, deputy commander of the Revolutionary Guards ground forces, General Mohammad-Zadeh, commander of the Revolutionary Guards in Sistan-Baluchestan province, the Guards' commander for the town of Iranshahr and the commander of the Amir al-Momenin unit died," the news agency reported.
Parliamentary speaker Ali Larijani confirmed the officers' death in an announcement to parliament which was broadcast on television.
"The goal of the terrorists is to disturb the security of the Sistan-Baluchestan province," he told parliament. "It shows they do not want to have economic progress in this region. But certainly the Guards will act with more force to establish security in the region."
Iran has previously accused shadowy Sunni group Jundallah (Soldiers of God) of launching regular attacks in the province, which borders both Afghanistan and Pakistan.
The mostly Shiite Sistan-Baluchestan is home to a sizeable Baluch minority which adheres to Sunni Islam.
Jundallah is strongly opposed to the government of predominantly Shiite Iran.
Source: The Australian