Kyrgyzstan's opposition said on Thursday it had seized power in the impoverished and strategically important Central Asian state after an uprising forced President Kurmanbek Bakiyev to flee the capital.

With rioters roaming the streets and widespread looting after a day in which dozens were killed in clashes between protesters and police, the self-proclaimed new interior minister ordered security forces to fire on looters.

UN Secretary General Ban Ki-moon said it was crucial to restore order in Kyrgyzstan after the turmoil set off by social and economic unrest.

Roza Otunbayeva, leader of the interim government, demanded the resignation of the president, whom she helped propel to power five years ago. But a local news agency cited Bakiyev as refusing to step down.

Otunbayeva said Bakiyev, who fled while security forces fired on protesters besieging government buildings on Wednesday, was trying to rally supporters from his southern power base.

'What we did yesterday was our answer to the repression and tyranny against the people by the Bakiyev regime,' said Otunbayeva, who once served as Bakiyev's foreign minister.

'You can call this revolution. You can call this a people's revolt. Either way, it is our way of saying that we want justice and democracy,' she told reporters.   

While refusing to resign, Bakiyev also echoed opposition statements that the army and security forces were under opposition control, a local news website said.

Bishkek awoke to blazing cars and burned-out shops on Thursday after a day in which at least 75 people were killed in the bloody clashes between protesters and security forces.   

Plumes of smoke billowed from the White House, the main seat of government, as crowds rampaged through the seven-storey building setting several rooms on fire. Looting was widespread.  

'It is time to work urgently in establishing constitutional order,' Ban said in an address to the Organisation for Security and Co-operation in Europe (OSCE) in Vienna.

The uprising, which began on Tuesday in a provincial town, was sparked by discontent over corruption, nepotism and rising utility prices in a nation where a third of the 5.3 million population live below the poverty line.

The United States and Russia both have military bases in Kyrgyzstan and are, along with China, major donors to the former Soviet state. NATO said flights from the US base in support of its operations in Afghanistan were suspended due to the unrest.   

Russia was quick to recognise Otunbayeva's takeover. Washington declined to comment on the recognition. China said only that it was deeply disturbed by the unrest. The European Union said only that the country was 'entering a new phase'.

Russian Prime Minister Vladimir Putin's spokesman said Otunbayeva had told him by telephone she was in full control of the country and he saw her as 'the new head of government'.   

Putin earlier denied Moscow had played a hand in the clashes and Otunbayeva said the new government would allow the US base in the Kyrgyz city of Manas to continue to operate while adding that 'some questions' over it would be resolved.

Bakiyev announced the base would close during a visit to Moscow last year at which he also secured $2 billion in crisis aid, only to agree later to keep the base open at a higher rent. 

Bakiyev fled Bishkek to southern Kyrgyzstan, his traditional power base in a nation split by clan rivalries. A witness said he arrived late on Wednesday at the airport in Osh, and Otunbayeva said later he was in his home region of Jalalabad.   

'We want to negotiate his resignation,' she said. 'His business here is over ... The people who were killed here yesterday are the victims of his regime.'    

She said the interim government controlled the whole country, except for Osh and Jalalabad. Armed forces and border guards supported the new government, she said. There has been no word from Bakiyev and his spokesmen were not available.   

In the centre of Osh, hundreds of Bakiyev's supporters scuffled on Thursday with opponents, who took control of the government building, a Reuters reporter said.   

Many of those who died in the capital suffered gunshot wounds. Protesters stormed the government building that Bakiyev left behind, smashing trucks through the perimeter fencing.   

The US-led Nato alliance said the interruption to flights through Manas should not significantly affect operations or logistical support in Afghanistan.

Bakiyev came to power in the 2005 'Tulip Revolution' protests, led jointly by Otunbayeva, which ousted Kyrgyzstan's first post-Soviet president, Askar Akayev. She briefly served as acting foreign minister before falling out with Bakiyev.   

The opposition said at least 100 people had been killed on Wednesday after security forces opened fire with live ammunition. The Health Ministry put the death toll in Bishkek at 75 dead, and said more than 1,000 people had been injured.

In her first major policy statement, Otunbayeva said she would cut utility prices and return certain assets she said were 'illegally privatised', referring to two power companies.   

Analysts said the unrest would also increase uncertainty for foreign investors in Kyrgyzstan's mining sector and would have an impact on US interests in Central Asia. - Reuters