Some 300,000 people are expected to take part in the event marking Khomeni's death, according to the Tehran Times. The anniversary is marked annually with a ceremony at his tomb attended by the Supreme Leader and other Iranian officials. The event usually features a speech by Supreme Leader Ayatollah Ali Khamenei.
Old American Hawk anti-aircraft missile systems from before the 1979 Islamic Revolution have also been deployed as part of the preparation, claimed Mohammad Reza Yazdi, the commander of the IRGC in Tehran, on Saturday.
These missile systems were most recently used near the Arak nuclear reactor in 2010, according to Fars news.
No reason was given for why anti-aircraft batteries are on alert for Khomenei's death anniversary, but some Iranian officials, including the former chief of Iran's state TV, Mohammad Sarafaz, had speculated in early May that Iran might be attacked by the end of Ramadan, which ends on June 4.
Tensions have risen between Iran and the United States after Washington sent more military forces to the Middle East in a show of force against what US officials say are Iranian threats to its troops and interests in the region.
Acting US Defense Secretary Patrick Shanahan on Thursday confirmed that the Pentagon was considering sending additional US troops to the Middle East as one of the ways to bolster protection for American forces there.
Yazdi did mention the threat of small flying objects, adding that preparations have been made to counter such threats. Radio Farda posited that Yazdi was referring to the threat of drones. Yazdi stated that there were no reports of any activity of such flying objects, but added that "we are planning to show our capability."
Terrorist attacks are also a viable threat, such as the ISIS attack on the Iranian parliament and Khomeini's tomb in June 2017 and an attack on an IRGC parade in Ahvaz in September 2018, Radio Farda reported.
Yazdi warned that "those who might be planning to disrupt order and security in this year's gathering on June 13 - 15 not to waste their time, as security forces will confront them seriously."Reuters contributed to this report.