Iran vowed Monday an "immediate" response to the European Union as it prepares new sanctions on the Islamic republic after over a month of protests sparked by Mahsa Amini's death.

EU foreign ministers met Monday to adopt sanctions on Iran, including on the morality police in whose custody Amini died on September 16 after she was detained for allegedly breaching Iran's strict dress code for women.

Iran will "decide and act immediately in accordance with the decisions and actions" taken by EU member countries, foreign ministry spokesman Naser Kanani said.

"If they initiate new sanctions, this action is definitely unconstructive and irrational."

Iran has been rocked by demonstrations since the death of 22-year-old Amini and a crackdown on protesters.

European Commission chief Ursula von der Leyen warned last week that "now is the time to sanction those responsible" in Iran "for the repression of women".

The planned EU sanctions target 11 Iranian officials and four entities, including the morality police, who will be subject to EU visa bans and asset freezes.

The United States, Britain and Canada have already announced sanctions against Iran over rights violations.

Tehran has accused the United States and some US allies of fomenting the protests.