Mousavi and Karroubi have been held incommunicado under separate house arrests since February 2011, accused of orchestrating massive, unprecedented street protests sparked by a disputed presidential election in 2009.
Prosecutor general Gholam Hossein Mohseni Ejeie said they had committed a "great crime and treason".
"Until time the sedition leaders (agree to) repent... The situation will remain as before," he said.
The protests turned deadly when authorities resorted to a heavy-handed crackdown in which thousands of protesters, reformist activists and journalists were arrested.
"Some people are pointlessly trying to lift the house arrests, but (their efforts) will not bear any fruit," said Mohseni Ejeie, without further details.
The fate of Mousavi and Karroubi- both of whom are reportedly suffering health problems- has attracted global attention and triggered heated debates at home.
In December influential Iranian lawmaker Ali Motahari, a conservative, said the judiciary should end the house arrests of Mousavi and Karroubi on put them on trial.
"The protracted house arrests without trial lack legal or religious justification," Motahari told parliament in remarks carried by the ISNA news agency.
President Hassan Rouhani, a reputed moderate, pledged after his election victory in June 2013, to work for political and cultural liberalisation in Iran.
But he has stopped short of becoming directly involved in the case of Mousavi and Karroubi.
But in September, the authorities freed around 15 reformists, journalists and lawyers, notably prominent rights lawyer Nasrin Sotoudeh.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
