Iranian security forces have arrested 14 foreigners, including American, British, and French citizens, for their involvement in anti-government protests, the semi-official Fars news agency said on Wednesday.

Iranian officials have yet to comment.

Iran has blamed "thugs" linked to "foreign enemies" for the nationwide protests that erupted after the death in custody of 22-year-old Mahsa Amini on Sept 16.

"Citizens of 14 countries, including the United States, Russia, Austria, France, the United Kingdom, and Afghanistan, have been arrested in recent riots in Iran, of which Afghan nationals are the most numerous," Fars reported, without citing a source.

Fars, believed to be affiliated with Iran's Revolutionary Guards, did not say when and where the arrests were made.

It was not immediately clear whether the reported arrests included nine foreigners who Tehran said last month had been detained for their role in the protests.

The nationwide protests, sparked by Amini's death in the custody of Iran's morality police, have turned into one of the boldest challenges to Iran's clerical rulers since the 1979 revolution. Protesters have called for the downfall of the Islamic Republic, although the protests do not seem close to toppling the system.

Tehran has accused the United States and some European countries of using the unrest to try to destabilise the Islamic Republic.

- Reuters