CAIRO (AP) - Iran’s top electoral body said Tuesday it found "no major fraud" and will not annul the results of the June 12 election, closing the door to a do-over sought by angry opposition supporters alleging systematic vote-rigging.

Since the vote, Iranian government officials have repeatedly suggested that a revote is extremely unlikely. However, Tuesday’s announcement by Iran’s top electoral body, the Guardian Council, was the clearest yet in ruling out a do-over.

The announcement on Iran’s state-run English language Press TV is another sign the regime is determined to crush post-election unrest, the worst since the 1979 Islamic Revolution, rather than seek compromise with the protesters.

Government warnings to the protesters have intensified in recent days, with Iran’s supreme leader ordering them off the streets and the feared Revolutionary Guards threatening a tough crackdown. At least 17 people have been killed in near-daily demonstrations, including at least one that drew hundreds of thousands of people.

In a boost for the embattled regime, Russia said Tuesday that it respects the declared election result, which the Iranian government described as a landslide victory for hardline President Mahmoud Ahmadinejad. The U.S. and many European countries have refrained from challenging the election outcome directly, but have issued increasingly stern warnings against continuing violence meted out to demonstrators.

Ahmadinejad’s main challenger, Mir Hossein Mousavi, has charged the election was a fraud and insists he is the true winner.

The Guardian Council found "no major fraud or breach in the election," a spokesman, Abbas Ali Kadkhodaei, was quoted by Press TV as saying. "Therefore, there is no possibility of an annulment taking place."

On Monday, the Guardian Council said - in a rare acknowledgment - that there had been voting irregularities in 50 districts, including local vote counts that exceeded the number of eligible voters. However, the council said the discrepancies were not widespread enough to affect the result.

Ahmadinejad won crucial backing from Russia on Tuesday, with the Foreign Ministry in Moscow saying it respects the declared election result. In a statement on its Web site, the ministry said that disputes about the vote "should be settled in strict compliance with Iran’s Constitution and law" and are "exclusively an internal matter."