The UNSC has "condemned in the strongest terms the attacks against United Kingdom's embassy in Tehran", said a statement read out by Portuguese UN Ambassador Jose Filipe Moraes Cabral, who is the council president for November.

The members recalled the fundamental principle of "inviolability of diplomatic and consular premises", and obligations on host governments "to take all appropriate steps to protect diplomatic and consular premises against any intrusion or damage," Xinhua quoted Cabral as saying.

Thousands of Iranians staged a protest before the British Embassy in Tehran early Tuesday, and 100 of them broke into the compound.

British flags at the embassy and the British Council were dragged down by the protesters and replaced them with the Iranian national flags.

The rampage came a day after Iran's highest legislative body, Guardian Council of the Constitution, unanimously approved reducing the diplomatic ties with Britain in response to its " hostile" policy against Iran.

Britain severed all links with the Iranian banks last week as part of its new financial sanctions in the wake of a report by the International Atomic Energy Agency that expressed concern over Tehran's controversial nuclear programme.