Foreign Minister Manouchehr Mottaki said Wednesday Iran is reviewing whether to downgrade ties with Britain, accusing London of meddling in the post-election tumult gripping the Islamic republic. “We are examining it,” he was quoted by the ISNA news agency as saying, after repeated charges by Tehran that Britain and the United States are trying to destabilize Iran. His announcment came a day after British Prime Minister Gordon Brown announced the expulsion of two Iranian diplomats in a tit-for-tat move after Tehran ordered two British diplomats to leave. Meanwhile, Iran's Supreme Leader Ayatollah Ali Khamenei declared Wednesday that the disputed election result would stand despite street protests. “I had insisted and will insist on implementing the law on the election issue,” Khamenei said. “Neither the establishment nor the nation will yield to pressure at any cost.” The furore over the election has exposed deep rifts within Iran's political elite, with Khamenei solidly backing Ahmadinejad against Mousavi, who has the support of former presidents Akbar Hashemi Rafsanjani and Mohammad Khatami. Many of Iran's senior Shi'ite clerics in the holy city of Qom have stayed out of the political fray, although Grand Ayatollah Hossein Ali Montazeri has called for three days of national mourning from Wednesday for those killed in protests. Up to 20 people have been killed in the protests, according to Iran's state English-language Press TV. Amateur footage of clashes with security men, and of some of the deaths, has been posted on the Internet and viewed around the world. Mousavi's wife, Zahra Rahnavard, demanded the immediate release of people detained since the election – who include 25 employees of her husband's newspaper -- and criticised the presence of armed forces in the streets, his website reported. “It is my duty to continue legal protests to preserve Iranian rights,” Rahnavard, who actively campaigned with her husband before the election, was quoted as saying. Intelligence Minister Gholamhossein Mohseni-Ejei said some British passport-holders had been involved in “riots”, Fars news agency reported.