At a ceremony marking the 21st anniversary of the death of Ayatollah Ruhollah Khomeini, hard-liners shouted down his grandson and disrupted his speech with chants of "Death to Musavi!" Check out a video of Hassan Khomeini's speech here.
Musavi said in a statement published on the Kalame website that the verbal attack against Khomeini was a pre-planned move aimed at eliminating him from Iran's political scene.
Iran's largest reformist political party, the Participation Front (Mosharekat), said in an open letter to senior clerics in Qom that those behind Friday's incident are against an independent clergy. The Participation Front said that by attacking Hassan Khomeini, "some well-known and organized" groups are trying to create fear among the clergy.
Ali Shakourirad, a member of the Participation Front, has said that Khomeini is paying the price of his support for the people in their pain and suffering during the last year.
A conservative legislator, Ali Motahari, also condemned the verbal attack against Hassan Khomeini as a "bitter event" that went against "the principles of the Islamic Revolution, including freedom of expression." He said that Iranian President Mahmud Ahmadinejad had "a major role" in Friday's incident.
Motahari said in a statement published on Tabnak that if the judiciary had put on trial the elements of the "sedition" -- which he named as Mir Hossein Musavi, Mehdi Karrubi, and also Ahmadinejad -- Friday's events would not have happened.
"Ahmadinejad has become like the darling kid of a family who is encouraged for causing harms to others," Motahari was quoted as saying.
Motahari added that he is not defending Hassan Khomeini but believes he should have been given the right to speak.
"Maybe Seyed Hassan wanted to criticize Musavi and Karrubi. So we should have listened to him and chanted slogans if we didn't agree with him," he said. "We shouldn't have agreed several days ago that he shouldn't have the right to speak."
The opposition Jaras website reports that students at Shiraz University chanted "Allah Akbar" and other protest slogans on Friday evening to protest the "disrespect" shown to Hassan Khomeini.
WATCH: A video clip titled "Seyed Hassan Is Not Alone" is making the rounds in support of Hassan Khomeini.
The attack against Khomeini's grandson is another example of the fissures within Iran's Islamic establishment that were created or which have deepened since last year's disputed presidential election. Both sides -- hard-liners and reformists-- are claiming they are the true followers of the legacy of Ayatollah Khomeinei.
-- Golnaz Esfandiari