TEHRAN, Iran — Iran's supreme leader warned Western governments on Monday of a "negative impact" on relations due to what he called their meddling in Iran's post-election riots, state television reported.

The comments by Ayatollah Ali Khamenei reflect continued efforts by the regime to blame Western powers such as the U.S. and Britain, not internal anger, for widescale unrest following the country's disputed presidential election. They also come one day after the American vice president said the U.S. is still open to negotiating with Iran over its nuclear program.

"Some leaders of Western countries at the level of president, prime minister and foreign minister openly intervened in Iran's internal affairs that had nothing to do with them. Then, they said they don't intervene in Iran's internal affairs," the television quoted Khamenei as telling thousands of Iranians during a ceremony to commemorate a revered Shiite saint.

Iran quashed street protests following its disputed June 12 election, and the leadership has been trying to erase any lingering doubts about the legitimacy of President Mahmoud Ahmadinejad by portraying the unrest as sparked by foreign meddling.

Reformist opposition leader Mir Hossein Mousavi has said the government has stolen the election results and that he was the rightful winner of the vote, not Ahmadinejad. Khamenei has sided with Ahmadinejad over the dispute.

While the regime has managed to silence the protests challenging the election results, the demonstrations and continued opposition being voiced by reformist politicians and their allies through other channels has produced a rare challenge in a country where the supreme leader's word is supposed to be final.

Khamenei said Monday that Iran will pay attention to the remarks and behaviors of Western governments and said that it will definitely have a negative impact on future relations with Iran.

"These governments must be careful of their hostile remarks and behaviors because the Iranian nation will" react, the television quoted Khamenei as saying. "We will calculate the interventionst remarks and behaviors of these governments. Definitely, it will have a negative impact on future relations with the Islamic Republic of Iran."

In the post-election fallout, Iran detained hundreds of activists, journalists and bloggers, although most have been released. The country also detained nine local employees of the British Embassy, leading to vocal protests from Britain and the European Union.

Britain's Foreign Office said Monday that Iran has released another British Embassy staff member, leaving one employee still in custody.