The sanctions, first imposed in 2011, include an asset freeze against 82 individuals and one entity, plus a ban on exports to Iran of equipment "which might be used for internal repression and of equipment for monitoring telecommunications".

The European Council of member states said it decided to extend the sanctions -- which are not related to the 2015 deal to curb the Islamic republic's nuclear ambitions -- in response "to serious human rights violations in Iran".

The measures were first put in place following a crackdown during the 2009 election and subsequent protests sparked by the Arab Spring which inspired hopes of reform in Iran.

Britain, France and Germany -- the three European countries that signed the Iran nuclear deal -- are working to head off US President Donald Trump's threat to walk away from the accord and reimpose stinging economic sanctions by May 12.

Trump has repeatedly condemned the deal and demanded tough new restrictions on Iran over its ballistic missile programme and its role in conflicts around the Middle East.