Tens of thousands of Iranian mourners turned the funeral procession of the country's most senior dissident cleric into an anti-government protest Dec. 21, chanting "death to the dictator" and slogans in support of the opposition amid heavy security.

A mourner holds a portrait of Grand Ayatollah Hossein Ali Montazeri during his furneal in Qom, Iran on Dec. 21 AP PHOTO

Giant crowds filled major streets, beating their chests in mourning, waving banners in the green colors of the opposition and shouting denunciations of Iran's rulers as Grand Ayatollah Hossein Ali Montazeri's body was carried to a shrine in Iran's holy city of Qom.

Some mourners clashed briefly with security forces, throwing stones — and hard-line pro-government militiamen charged some protesters until police held them back, opposition Web sites said. The militiamen tore down mourning banners and ripped to pieces posters of Montazeri near his home, the Hammihan Web site reported.

The death of Montazeri on Dec. 20, at the age of 87, pushed Iranian authorities into a difficult spot. They were obliged to pay respects to one of the patriarchs of the 1979 Islamic Revolution and the one-time heir apparent to Ayatollah Ruhollah Khomeini.

But officials also worried that his mourning rites could give a new push to opposition protests, particularly because they coincide with a week of traditional rallies commemorating a revered Shiite martyr. Montazeri broke with Iran's clerical leadership and became a vehement critic, denouncing Supreme Leader Ayatollah Ali Khamenei and calling the postelection crackdown the work of a dictatorship.