An angry crowd stormed the Kyrgyz government headquarters and the national television station Thursday in a violent uprising that left dozens injured as opposition leaders claimed to have taken control of the government.

By nightfall, President Askar Akayev's whereabouts were unknown, while unconfirmed reports said he had resigned and fled the country, as looting and chaos reigned in the capital.

Opposition leader Kurmanbek Bakiyev said on state television, now under opposition control, that Akayev's prime minister, Nikolai Tanayev, had also resigned.

Interfax reported that Akayev had flown to Russia while his family was evacuated to Kazakhstan, citing unidentified sources, but later said his plane had been rerouted and flown to Kazakhstan. Government officials could not be contacted for confirmation.

Late Thursday, the outgoing Kyrgyz parliament elected a former opposition lawmaker, Ishenbai Kadyrbekov, as interim president and asked the opposition to form a new government.

The parliament convened after the country's Supreme Court ruled that elections last month, described as deeply flawed by international observers, were invalid.

Earlier in the day a key opposition leader, Felix Kulov, was released from prison by a crowd of opposition supporters and went on television to urge Akayev to resign.

'Askar Akayev is guilty of all that has happened here,' Kulov said.

Kulov, a former vice president considered by many to be the charismatic leader who could unite the country's fractious opposition, was jailed in 2000 on charges of embezzlement that his supporters said were politically motivated.

Opposition leaders said they planned to hold new parliamentary and presidential elections in the coming months. Akayev had previously said he would step down as president when his term ran out in October, but the opposition claimed he was angling to retain power, possibly through setting up a family dynasty.

Akayev's son Aidar and daughter Bermet were elected to parliament in the disputed elections, which returned a big majority of pro-Akayev deputies. A first round of elections on Feb. 27 was followed by runoffs March 13.

Protests against the election results have rocked the country over the last week, with towns across a swath of southern Kyrgyzstan, including the second-largest city, Osh, falling to opposition supporters in rapid succession.

In Bishkek, thousands of protesters, many of them from outside the capital, assembled near the presidential administration in a tense standoff with riot police shortly after noon. Violence erupted after a group of young men, apparently from Osh, pressed forward toward government forces.

The crowd fought a pitched battle with riot police and Defense Ministry troops guarding the White House -- the location of both the presidential administration and parliament -- before overpowering the far-outnumbered riot police. The police, who numbered about 100, were not visibly carrying guns.

Protesters surged through the gates of the White House in a scene reminiscent of the storming of the Winter Palace in Sergei Eisenstein's film 'October,' smashing windows on the ground floor and piling in.

Top security officials, including Defense Minister Esen Topoyev, were captured and bundled out of the building, with some protesters protecting them from injury and others attacking them.

Some protesters were badly beaten in the melee. One man lay on the square with one of his legs badly twisted at the knee, blood spilling onto the pavement.

Inside the White House, an unruly and chaotic atmosphere prevailed. Young men with sticks and stolen riot shields and wearing yellow and pink headbands ran amok in the corridors, ransacking rooms and spilling documents on to the floor. Protesters smashed windows and waved Kyrgyz flags at crowds cheering below.

Some stole anything they could carry, although opposition leaders tried to stop the looting. A group of young men even raided the kitchen outside Akayev's seventh-floor office, making off with bottles of expensive liquor and cans of beans. One young man, with what appeared to be a miniature golden Statue of Liberty poking out of his satchel, boasted he was wearing one of Akayev's ties.

Near Akayev's office, an old man scuffled with one of Akayev's secretaries, berating her for owning an expensive jacket while he was out of work.

An officer standing near Akayev's office said there were enough weapons and ammunition inside the building to stop the crowd, but troops had been ordered not to fire.

Bakiyev, the chairman of the opposition's coordinating council, gave an impromptu speech in Akayev's office, saying no one had planned to ransack the White House. 'I did not expect this,' he said. 'I thought we would have a rally and appeal to the president. But because they did not come to the talks, this was the result.'

Bakiyev said that 'soldiers who support the people' would be organized to guard the White House.

Opposition activist Ulan Shambetov sat in Akayev's chair and said that not the opposition, 'but the people ... have taken power. They have been fighting for so long against corruption, against [Akayev's] family,' he said.

About 20 Defense Ministry troops filed out of the main entrance after the crowd took control of the building. Some were injured, with bandages on their heads and blood streaming down their faces. Eventually, opposition leaders sent most of the protesters out of the building.

Protesters stood outside the White House after the building had been cleared, basking in their triumph. Many said their hatred for Akayev, rather than support for particular opposition figures, was what brought the crowd together.

Asked which party or candidate he would support in the next elections, one of the protesters, Marat Begaliyev, 63, said it was not an issue.

'I don't need a party,' he said. 'I'm going to vote for the truth.' He said Thursday's violence was regrettable, but that in his opinion, democracy had prevailed. 'In Georgia, in Ukraine, it was calm and peaceful there,' he said. 'But we are a fiery people. We waited a month, and that was long enough.'

By Thursday night, central Bishkek was the scene of mass looting and a few scattered, unexplained explosions.

Hundreds of people were seen carrying looted microwaves, television sets and other appliances. The looters appeared to be mainly targeting businesses owned by Akayev's family.

In Moscow, Foreign Minister Sergei Lavrov expressed concern at Thursday's uprising and called for law and order to be restored. 'Today we confirmed our serious concerns about the consequences that can arise from attempts to come to power by illegal methods,' he said, Interfax reported.

'According to reports, some actions have already led to human casualties,' he said.

Foreign Ministry spokesman Alexander Yakovenko also warned about the risk of further violence and said in a statement that he hoped the situation in Kyrgyzstan would be resolved according 'to the framework of the law.'

Russia has a military base in Kyrgyzstan, as does the United States. It was unclear how Akayev might have fled the country.

Yury Baluyevsky, chief of the General Staff, criticized the Kyrgyz opposition severely over the uprising.

'I'd like to believe and hope that the actions of a mob high on narcotic substances will not totally destabilize this republic, which is not only our close neighbor but also a signatory to the Collective Security Treaty,' he said, Interfax reported.

U.S. Defense Secretary Donald Rumsfeld, on a visit to Guatemala, said Thursday that he could not verify whether Akayev had left Kyrgyzstan or where he might have gone.