British police said on Monday that 12 people were arrested and at least five police officers were seriously injured after violent disorder broke out during protests outside the Iranian Embassy in London.
Large crowds had gathered all week outside the compound to protest the death of 22-year-old Mahsa Amini in custody in Iran after she was detained by the country's morality police.
The Metropolitan Police force said most protesters had been peaceful, but on Sunday a group of activists sought to confront police and other protesters with different views.
Police said bottles and other items were thrown at officers trying to protect the embassy building, and that protesters also targeted the nearby Islamic Centre of England.
At least five officers were hospitalised with injuries including broken bones, police said.
Amini was arrested for allegedly breaking headscarf rules and died on September 16.
The Iranian police said she died of a heart attack and wasn't mistreated, but her family has cast doubt on that account.
The London clashes came as protests over her death spread across dozens of Iranian cities, towns and villages.
Iran's Foreign Ministry said Sunday it summoned Britain's ambassador to protest what it described as a hostile atmosphere created by London-based Farsi language media outlets.
The ministry alleged the news outlets have provoked disturbances and the spread of riots in Iran at the top of their programs.