Iran has blacklisted US-based think-tank the Foundation for Defense of Democracies and its chief Mark Dubowitz on accusations of being behind "economic terrorism" against the Islamic republic.
The Iranian foreign ministry said in a statement issued late Saturday that it had "added the so-called Foundation for Defence of Democracies (FDD) and its director to the sanctions list".
"The American institution with the deceitful name" and Dubowitz were accused of being involved in "designing, imposing and intensifying the impacts of economic terrorism against Iran", it said.
The FDD and Dubowitz were blamed for "seriously and actively trying to harm the Iranian people's security and vital interests", according to the English-language statement posted on the ministry's website.
They were accused of doing so through "fabricating and spreading lies, encouraging, providing consultations, lobbying, and launching a smear campaign" against Iran.
As a result, they would be "subject to legal consequences", it said.
The move would be "without prejudice to any further legal measures that the other administrative, judicial or security institutions and organisations may take" against them and their "collaborators and accomplices".
The FDD describes itself as a Washington-based "non-partisan research institute focusing on national security and foreign policy".
The think-tank responded to Tehran's move with a statement saying, "FDD considers its inclusion on any list put out by the regime as a badge of honour and looks forward to the day when Americans and others can visit a free and democratic Iran".
It strongly opposed the 2015 deal that saw world powers lift sanctions against Iran in return for limits on its nuclear programme.
Tensions between arch-foes Iran and the United States have escalated since President Donald Trump unilaterally withdrew the US from the accord last year and began reimposing sanctions against the Islamic republic.
The Iranian foreign ministry said in a statement issued late Saturday that it had 'added the so-called Foundation for Defence of Democracies (FDD) and its director to the sanctions list'.