Britain says it is expelling Iranian diplomats from the country and has ordered the immediate closure of the Iranian embassy in London.
Foreign Secretary William Hague announced the decision on Wednesday, a day after protesters mobbed British embassy compounds in Tehran.
On Tuesday, British Prime Minister David Cameron had said Iran faced “serious consequences” for failing to defend the British compounds from Islamists who smashed embassy windows and ransacked offices as police looked on.
The Islamists had gathered outside the buildings in a reflection of government anger at British sanctions imposed on Iran last week for pursuing an alleged nuclear weapons program.
Britain initially responded by saying it was withdrawing some of its diplomatic staff from Iran.
Meanwhile, Norway has closed its mission in Tehran following Tuesday's mob assaults.
The attacks drew more international criticism Wednesday. U.N. Secretary-General Ban Ki-moon's office said he expressed shock and outrage as he met with a British official on the sidelines of an aid conference in South Korea.
The U.N. chief called on Iran to investigate the British embassy break-in and take measures to avoid any repetition there or at other diplomatic missions.
U.S. Secretary of State Hillary Clinton also strongly condemned the assaults as an “affront not only to the British people but also to the international community.”
She said Washington expects Iran to protect the lives and properties of diplomats in accordance with international conventions.
China's foreign ministry said the embassy attacks were “contrary” to international law and norms and should be dealt with “appropriately.” It was a rare Chinese criticism of Iran, a key supplier of energy to the Chinese economy.
Iranian parliament speaker Ali Larijani said Wednesday Iranian police tried to maintain calm during the assaults.
Britain, the United States and Canada announced coordinated economic sanctions against Iran last week in response to Iran's pursuit of a nuclear program that U.N. experts say appears designed to build weapons. Iran says its nuclear program is peaceful.
