Mir Hossein Mousavi's  accused hard-line politicians of moving toward an oppressive, one-party system, something that the pro-Western Shah Mohammad Reza Pahlavi did in his last years in power by outlawing all but his Rastakhiz party.
 

"Pahlavi in the final years of the former regime declared Rastakhiz as the only party authorized to operate in the country and we all saw what his fate was," Mousavi said in comments posted on his website Monday.
 

Mousavi, a former prime minister, was a fervent supporter of the 1979 revolution that threw out the Shah and brought cleric-led government to Iran before recasting himself as a leader of the reform-seeking opposition in last year's disputed presidential election.
 

The protesters that swept Iranian cities after the vote claimed Mousavi was robbed of the presidency through election fraud. Later, their criticism widened to target Iran's ruling establishment and its harsh crackdown on the demonstrators.
 

Mousavi’s comments were apparently triggered by statements earlier this month by President Mahmoud Ahmadinejad, who said Iran has only one party and that is the party of Velayat, a reference to the position of Supreme Leader Ayatollah Ali Khamenei.
 

"The existence of parties, political factions ... is necessary for the progress of the country," Mousavi said.

He said the government was now focused on "reproducing dictatorship."

(AP contributed to this report)