WASHINGTON, Dec. 24 (UPI) -- Iran is reacting to the durability of an opposition movement seeking government reform as if it were a police state, U.S. State Department officials said.

Commemorations for the late dissident cleric Grand Ayatollah Hossein Ali Montazeri turned violent in the Iranian city of Isfahan on Wednesday when security forces blocked access to a mosque scheduled to welcome mourners for official ceremonies.


Montazeri, once a student of the Islamic republic's founder Ayatollah Ruhollah Khomeini, emerged as the spiritual leader of the opposition movement in Iran that grew out of the contested victory for President Mahmoud Ahmadinejad in June elections.

The government in response to June clashes used force and widespread arrests to quiet the opposition. Security forces on Wednesday used batons, tear gas and chains to disperse the crowds in Isfahan.

P.J. Crowley, a spokesman for the U.S. State Department, said Tehran is "using all of its levers" to quiet the aspirations of a movement seeking a new relationship with the government.

"Iran is increasingly showing itself to be a police state," the spokesman said.

In a rare statement from Washington, the White House expressed its condolences on the passing of Montazeri, who died during the weekend, praising his "unwavering commitment" to human rights and recognizing "those who seek to exercise the universal rights and freedoms that he so consistently advocated."

Despite a major government crackdown, the opposition movement has used national holidays to stage demonstrations. The next major holiday is the Sunday festival of Ashura marking the anniversary of the death of the grandson of the Islamic prophet Mohammed.