Hard-line Iranian MPs have demanded opposition leaders be executed after anti-government demonstrations left one person dead and dozens injured.
Tens of thousands of people turned out on Monday in solidarity with Egypt's revolt in the first major show of strength from Iran's beleaguered opposition in more than a year.
At an open session of parliament on Tuesday, pro-government MPs chanted "death to Mousavi, Karroubi and Kahatami," referring to opposition leaders Mir Hossein Mousavi and Mahdi Karroubi, and former reformist president Mohammad Khatami.
More than 220 MPs said in a statement that the trio should be held responsible for the unrest. "We believe the people have lost their patience and demand capital punishment" for the opposition leaders, the statement said.
Hard-liners have long sought to put high-ranking opposition figures on trial, but the calls for the death penalty signalled an escalation in their demands.
Authorities appeared to be moving quickly in a bid to stifle the opposition before it gains momentum, issuing promises of swift action against leaders and activists, the official IRNA news agency reported.
"The judiciary will quickly and resolutely deal with major elements and those who violated public order and peace," a spokesman for Iran's judiciary and state prosecutor said.
After Monday's protests US Secretary of State Hillary Clinton expressed support for the demonstrators, saying they "deserve to have the same rights that they saw being played out in Egypt and are part of their own birthright".
Iran's Foreign Ministry rejected her remarks, and accused the US of "meddling" in Iranian affairs.
Officials in Iran also confirmed that a 26-year-old student was killed in Monday's protests.