TEHRAN – Iran's Supreme Leader Ayatollah Ali Khamenei warned Western countries on Monday against interfering in Iranian affairs after its disputed presidential election, state television reported.

Iranian authorities accuse the West, particularly the United States and Britain, of inciting unrest in the Islamic Republic following the June 12 vote in which hardline President Mahmoud Ahmadinejad was re-elected.

We strongly warn leaders of some Western countries not to interfere in Iran's internal matters ... The Iranian nation will react, Khamenei said.

Last month's election, which defeated candidate Mirhossein Mousavi said was rigged, led to the most widespread street protests in Iran since the 1979 Islamic revolution.

Authorities say more than 1,000 people were arrested during the demonstrations, although most have been released. But human rights activists say 2,000 people, including opposition leaders, academics, journalists and students, may be still held.

Britain said on Monday that Iran had freed one of its last two embassy employees detained after the election, leaving just one still in custody. Iran accuses the Iranian employees of instigating street protests, a charge Britain denies.

It remains our top priority to get all of our embassy staff released as soon as possible, a Foreign Office spokeswoman said. We are continuing intensive discussions with the Iranian authorities and our international partners to resolve this.

European Union countries summoned Iranian ambassadors on Friday to protest at the detention of the British embassy staff and warned they would take tougher steps if they were not freed.

SARKOZY SAYS IRAN DESERVES BETTER LEADERS

Khamenei, who praised Ahmadinejad's victory even before an official review endorsed the result, said the vote was an internal Iranian issue.

The election was a major move ... The enemies want to create dispute among Iranians. What does it have to do with the enemies? he asked.

French President Nicolas Sarkozy, speaking shortly after Khamenei, said Iranians deserved better leadership and pledged to support Britain in its standoff with Tehran.

Really, the Iranian people deserve better than the leaders they have today, he said at a news conference with British Prime Minister Gordon Brown, pledging France's full support for Britain in the dispute over the embassy detentions.

We are totally in solidarity with our British friends vis-a-vis the Iranian leadership. They can count on our total solidarity, Sarkozy said.

We were particularly shocked by attacks on the British government that were very unjust, out of proportion.

Western criticism of Iran's post-election crackdown and Khamenei's rejection of Western interference appear to have dimmed prospects for dialogue over Iran's nuclear program, which the West fears could be used to build nuclear weapons.

Iran says its nuclear work is purely for civilian power generation, but it already faces three rounds of United Nations sanctions for its refusal to suspend uranium enrichment.

Israel has not ruled out a military strike against Iran to prevent it acquiring nuclear weapons and U.S. Vice President Joe Biden said on Sunday it was Israel's sovereign right to decide what was in its best interest in dealing with Tehran.

Farideh Farhi, a visiting scholar at the University of Hawaii, said it was not clear whether Iranian hardliners would shy away from U.S. President Barack Obama's offer of dialogue or accept talks to try to repair their dented domestic popularity.

The Obama administration is also under tremendous pressure not to engage with Iran at least on the broader scale that it had imagined, Farhi said.

Of course it has an incentive to engage in nuclear negotiations, sensing Iran's weakness on the domestic front. But for now it is taking a low-profile approach, essentially placing the ball in Khamenei's court, she added.

(Additional reporting by Hashem Kalantari in Tehran and Alistair Lyon in Beirut; Editing by Dominic Evans)