Iranian state agency IRNA quoted a representative of the Quds force as saying that the elusive leader of Daesh was dead but later the statement was withdrawn.
Iran appeared on Friday to backtrack on claims that Daesh's leader Abu Bakr al-Baghdadi had been killed.
The country's state news agency on Thursday quoted a representative of Iranian Supreme Leader Ayatollah Ali Khamenei as saying Daesh's leader Abu Bakr al-Baghdadi was no longer alive.
"Terrorist Baghdadi is definitely dead," IRNA quoted cleric Ali Shirazi, representative to the Quds Force, as saying, without elaborating.
IRNA later updated the news item, omitting the quote on Baghdadi's death.
The Quds Force is in charge of operations outside Iran's borders by the country's elite Revolutionary Guard Corps. Iranian Foreign Ministry officials were not available to comment on the report.
The secretive Daesh leader has frequently been reported killed or wounded since he declared a caliphate to rule over all Muslims from a mosque in Mosul in 2014, after his fighters seized large areas of northern Iraq.
Russia said on June 17 its forces might have killed Baghdadi in an air strike in Syria. Washington said on Thursday it had no information to corroborate such reports. Iraqi officials have also been sceptical in recent weeks.
Russian forces support the Syrian regime which is fighting against Daesh mainly from the west, while a US-led coalition supports Iraqi government forces fighting against Daesh from the east.