Britain says it is expelling two Iranian diplomats in retaliation for Iran ordering two British diplomats to leave Tehran in a dispute over Iran's contested election.

British Prime Minister Gordon Brown told lawmakers Tuesday Iran expelled the two diplomats the day before. Iran's government has accused Britain and other Western nations of interference by criticizing its crackdown on Iranians protesting the election results.

Mr. Brown says the diplomats' expulsion is unjustified and Iranian allegations of British meddling are "absolutely without foundation." He says Britain is expelling two Iranian diplomats from London with regret.

Iran also is accusing U.N. Secretary-General Ban Ki-moon of meddling after he urged the Islamic state to "immediately stop" arrests and the use of force against opposition activists.

Iran's foreign ministry says Mr. Ban is contradicting his duties and ignoring the facts about the June 12 presidential election. It accused the U.N. chief of being influenced by unspecified foreign powers.

Mr. Ban released a statement Monday urging Iran's conservative government and reformist opposition to peacefully resolve their dispute over the election. Official results gave a landslide victory to the conservative incumbent, Mahmoud Ahamdinejad.

White House spokesman Robert Gibbs says Washington believes recent mass protests over the election mark the "beginnings of change" in Iran, as he put it.

U.S. President Barack Obama has sharpened his criticism of Iran's government in recent days while trying to avoid the appearance of meddling. He is expected to address Iran's political crisis again in a news conference Tuesday in the White House Rose Garden.

Some opposition Republican lawmakers have criticized Mr. Obama's handling of the issue, saying the he is not taking a strong enough stand.

Gibbs told a U.S. television network Tuesday Mr. Obama does not want to become a "political football" that Iran's government uses against Iranians who seek justice. He says the Obama administration will not endorse Iranian opposition calls for a general strike.

In another development, several EU nations summoned Iranian ambassadors Tuesday to condemn Iran's post-election crackdown, including France, Sweden and Finland. The Czech presidency of the European Union lodged a similar protest Monday with Iran's envoy in Prague.

Meanwhile, Russia says it views the election controversy as an internal affair of Iran. It says disputes about the vote must be settled in strict compliance with Iran's constitution and law.