TEHRAN, Iran — The head of Iran’s opposition warned the country’s hard-line political leaders Monday that they could suffer the same fate as the deposed Shah if they continue to consolidate their grip on power.

The powerful comparison was Mir Hossein Mousavi’s first direct criticism of a ruling system that he was once firmly a part of and represented a bolder stance certain to provoke the authorities’ anger.

Specifically, he accused hard-liners 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.