Amateur videos said to be from the June 4 funeral appear to confirm the reports. RFE/RL cannot verify the authenticity of the videos.
The incident comes less than two weeks before Iran's presidential election and some four years after the brutal state crackdown following the previous election that silenced Iran's protest movement.
According to the reports, the antigovernment chants erupted in Isfahan at the funeral for Ayatollah Jalaledin Taheri Esfahani, the city's former Friday Prayers leader. Taheri, who was a critic of the clerical establishment, died over the weekend at the age of 87.
The Kalame website reports that tens of thousands of people and students from seminaries in Isfahan and other cities attended the funeral. Jaras, another website, put the numbers in the "thousands."
The participants reportedly called for the release of Iranian opposition leaders Mir Hossein Musavi and Mehdi Karrubi, who are under house arrest.
Musavi, a former prime minister and presidential candidate, and Karrubi, also a former presidential candidate and parliament speaker, have been under house arrest since February 2011. Musavi's wife, Zahra Rahvanard, is also under house arrest.
This video apparently shows the protesters chanting, "Oh Hossein, Mir Hossein!" and "Karrubi and Musavi must be released!"
There were also reportedly chants in support of late dissident Ayatollah Hossein Ali Montazeri, who was considered the spiritual father of Iran's opposition Green Movement. Montazeri's funeral in 2009 turned into a massive antiestablishment demonstration.
In this YouTube video allegedly from the funeral on June 4, chants of "Salam to Montazeri! Viva Taheri!" can be heard.
Kalame and Jaras report that "Death to the dictator!" "Dictator, dictator, may your sleep be disturbed!" and "Musavi, Karrubi, condolences, condolences!" were also among the protest chants.
Another video posted online shows people chanting "Death to the dictator!" and "The real clerics: Montazeri, Taheri."
Several protesters are said to have been detained.
Support For Rohani
Ayatollah Taheri described the disputed 2009 reelection of President Mahmud Ahmadinejad as "invalid." He resigned from his position as Isfahan's Friday Prayers leader in 2002 in protest against corruption and what he described as the broken promises of the revolution.
Hassan Rohani, who is a candidate in the June 14 presidential election and considered a moderate, attended Taheri's funeral. Slogans in support of opposition leaders Musavi and Karrubi were also chanted over the weekend at Rohani's campaign meeting in Tehran.
This video clip from the event shows the crowd calling for the release of political prisoners. They also chant, "Viva Musavi, welcome Rohani."
Several of Rohani's campaign staff were reportedly detained at the meeting. Some were released later.
Reports say prominent reformist figures, including former Interior Minister Abdollah Nouri and Mohammad Reza Khatami, the brother of former President Mohammad Khatami, were also present at Taheri's funeral. The son of Ayatollah Montazeri, Ahmad Montazeri, also attended.
-- Golnaz Esfandiari