The Iran Foreign Ministry summoned British ambassador Macaire to complain about his participation in "illegal march" in the capital, Tehran.

"Rob Macaire was summoned for acting in an illegal manner when participating in an illegal march on January 11," the Iranian Foreign Ministry released a statement today.

Iranian Deputy Foreign Minister Seyed Abbas Araghchi confirmed the arrest of Ambassador Macaire but confirmed that British officials were soon released when proving their identity. "He was arrested as an unknown foreigner at an illegal gathering," Deputy Minister Araghchi wrote on Twitter.

British Ambassador to Iran Robert Macaire yesterday attended a prayer for victims of the downing of an Ukrainian plane held outside Amir Kabir University in Tehran. However, the prayer was soon turned into a protest when hundreds of people shouted slogans to demand supreme leader Ayatollah Ali Khamenei to resign.

Iran's Tasnim news agency said the British ambassador and some were arrested for allegedly organizing, inciting and directing extremist acts, but it is not clear which forces arrested Mr. Macaire. Mr. Macaire was released after about an hour and returned to the embassy safely.

British Foreign Minister Dominic Raab called the incident "a blatant violation of international law". Ambassador Macaire said he only attended the prayers for the victims of a plane accident and was not involved in the protests.

Demonstrations in Iran erupted after the government admitted to accidentally shooting down the flight number PS752 of Ukraine International Airlines (UIA) on January 8, killing all 176 people aboard. Space forces commander of Iran's Islamic Revolutionary Guard took full responsibility, said the air defense complex misidentified its target and shot down the plane due to tensions with the United States.

Many Iranians question who ordered the shooting down of the aircraft, why Tehran did not close the international airport or airspace while preparing for a potential Washington counter. Protesters also demand that the people responsible for shooting down the plane and hiding the incident resign and be prosecuted.