The comments by Foreign Ministry spokesman Ramin Mahmanparast added to growing tensions between Iran and the West, which is threatening to impose tough new sanctions over Iran's suspect nuclear program and has criticized the violent crackdown on anti-government protesters in Tehran.
Iran has said as many as eight people were killed in Sunday's clashes in Tehran. There was no serious violence reported Tuesday, but opposition Web sites said several activists were arrested, including a prominent journalist and the sister of Nobel peace laureate Shirin Ebadi.
Speaking to reporters, Mehmanparast said the deadly clashes in Tehran were the work of a tiny minority, and he accused outside countries, including the U.S. and Britain, of "miscalculating" by siding with the protesters.
"Some Western countries are supporting this sort of activities. This is intervention in our internal affairs. We strongly condemn it," he said. "In this regard, the British ambassador will be summoned today."
He gave no further details, and there was no immediate reaction from Britain.
Britain, France, Germany and the U.S. have all criticized Iran's violent response to the protests, the bloodiest confrontations between the government and reformist activists since June's disputed presidential election.
On Monday, President Barack Obama praised "the courage and the conviction of the Iranian people" while condemning Iran's Islamic government for attacking demonstrators with "the iron fist of brutality."
Traveling with Obama in Hawaii, U.S. National Security Council chief of staff Denis McDonough also said the White House is reaching out to international partners to build support for a new round of sanctions against Iran. He said the U.S. was exploring both unilateral or U.N. sanctions.
The sanctions are to punish Iran for its refusal to halt uranium enrichment and accept a U.S.-backed plan to curb its nuclear program. The West suspects Iran is trying to build a nuclear bomb — a charge Tehran denies.
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