Nine European nationals including from Poland, France, Germany, Italy, Sweden and the Netherlands were arrested "at or behind the scene of riots", along with 256 members of outlawed opposition groups, Iran's intelligence ministry said on Friday.
Iran, which has blamed "foreign enemies" for protests that swept the country, said it had arrested the nine nationals for their role in the unrest.
The escalation comes as more casualties were reported in demonstrations across the country that has entered a third week amid gunfire.
Dozens have been killed in a crackdown on the protests that erupted when Mahsa Amini, 22, died in custody three days after her arrest by the notorious morality police in Tehran for allegedly breaching the Islamic republic's strict dress code for women.
Oslo-based Iran Human Rights group said 83 people were confirmed to have been killed in the protests, while Iran's Fars news agency has put the death toll at "around 60".
Source: Reuters, AFP