Ahmadinejad's victory greeted by Tehran protests

By Parisa Hafezi and Fredrik Dahl

TEHRAN (Reuters) - Thousands of protesters clashed with police after President Mahmoud Ahmadinejad won an election which his reformist challenger called a "dangerous charade."

The protests were a rare direct challenge to Iranian authorities. The result and its violent aftermath raised fresh questions about the direction of Iranian policies at a time when U.S. President Barack Obama wants to improve relations with Iran.

Supreme Leader Ayatollah Ali Khamenei told Iranians to respect Ahmadinejad's victory, which upset expectations that reformist candidate Mirhossein Mousavi might win the race.

Interior Minister Sadeq Mahsouli, an Ahmadinejad ally, declared the president had been re-elected with 62.6 percent of the vote, against 33.7 percent for Mousavi.

Mousavi complained of violations and vote-rigging -- allegations rejected by Interior Ministry officials.

"I'm warning I will not surrender to this dangerous charade. The result of such performance by some officials will jeopardize the pillars of the Islamic Republic and will establish tyranny," Mousavi said in a statement made available to Reuters.

After the result was announced, thousands of his supporters took to the streets, some chanting, "What happened to our vote?." Others shouted anti-Ahmadinejad slogans. "We are Iranians too," and "Mousavi is our president," they shouted.

Police beat protesters with batons as they spread out across the capital. Small fires burned at roadsides.