The looters had already taken the lampshades, the fridge, and the DVD player. Today they began on the shrubbery – digging up the dwarf fir trees from the front garden of Kyrgyzstan's president, Kurmanbek Bakiyev. The air resounded with crashing. One ambitious looter even stole the drainpipes.

The popular revolt in Kyrgyzstan that toppled Bakiyev two days ago was so sudden and ferocious that nobody has had a chance to give it a name yet. But it would be plausible to dub it the fir tree revolution – after the presidential shrubs taken and loaded into taxis.

Kyrgyzstan's opposition parties declared they had formed a new interim government, after a day of mayhem on yesterday when security force snipers and riot police opened fire on unarmed demonstrators as they tried to storm the main government building in the capital, Bishkek. At least 75 people were killed and 300 more injured.

Speaking in Bishkek's ransacked parliament building today, the opposition leader Roza Otunbayeva said: "You can call what happened here a popular uprising or a revolution. In essence people were simply fed up with the regime, and with its repressive, tyrannical and abusive ways."

Otunbayeva said her temporary government had taken control – with security headquarters, state TV and various government building now in opposition hands. She added that she planned to hold elections in six months after a new constitution had been drafted.

Out on the streets, however, there were few signs that the new regime was in control of anything. The police and security forces appeared to be hiding. Large crowds milled around the Soviet-era fir-tree-lined boulevards, forming and reforming revolutionary huddles. Dozens of shops had been looted. Burned out cars littered the pavements.

The main government building was on fire, with thick, black smoke pouring out of its upper floors. Hundreds of looters gathered near the White House presidential building. The shells of trucks and a tractor lay next to destroyed railings. Youths perched on an armoured personnel carrier, seized yesterday from government troops.

By late afternoon the general prosecutor's office was gutted, with gangs roaming around inside, smashing windows with broken-off table legs. Sheets of paper – followed by a fig plant – fell from a balcony. At the parliament building opposition workers were tossing posters of Bakiyev into the street.

Otunbayeva, a former foreign minister, said Bakiyev had fled the capital after yesterday's revolution and had taken refuge in the southern town of Jalal-Abad, on the Tajik border. Asked whether the new administration planned to arrest him, following yesterday's massacre, she replied: "He should resign. His business is finished in Kyrgyzstan."

But the prospect of prolonged instability was raised when Bakiyev later told a Russian radio station that he refused to stand down. Speaking to Ekho Moskvy from an undisclosed location, he said: "I don't admit defeat in any way … Even though I am president, I don't have any real levers of power."

Protesters said they had been driven to revolt by the decision to raise communal charges for water and electricity. The hikes had been the last straw in the country of five million people already wrestling with mass unemployment and widespread poverty. The unrest began in provincial cities on Tuesday, with locals seizing regional government buildings, before riots erupted in Bishkek.

Opposite the White House, Melis Deripasov was still incredulous at the security forces' reaction. "So many boys died. Two of my friends died. A young girl died just over there. The government used snipers against us," he said. "I'm unemployed. There is no work and no factories. Bakiyev stole everything. All that was left was the air we breathe."

This was the second revolution in five years Deripasov had taken part in. In 2005 pro-democracy demonstrators propelled Bakiyev into power, in the so-called tulip revolution.

But despite hopes that he would be a progressive ruler, critics say that Bakiyev turned out to be as greedy and illiberal as all other leaders in Central Asia. "This revolt was a cry from the soul. But I can't help feeling we deserved this president," Gulnura Bepeera said.

Kyrgyzstan is now at the centre of an geopolitical tussle between Moscow, Washington and Beijing. Russia's prime minister, Vladimir Putin, today phoned Otunbayeva and offered his support. She in turn thanked Russia for its "significant support" in exposing what she described as a "nepotistic, criminal regime".

The Kremlin was fed up with the Bakiyev regime, which it believed had fallen under US control. At issue is the US air base at Manas, near Bishkek, a key supply post for the US military and for Barack Obama's efforts to win the war in nearby Afghanistan. The Russians have been trying to turf the Americans out of the base. The opposition, now in power, had promised to do just that. Today, however, Otunbayeva said there would be no quick decisions: "Its status quo will remain in place. We still have some questions on it. Give us time."

But another former opposition leader now in a senior government role said there was a "high probability" that the US lease would be curtailed.

Much of the frustration directed at the ousted government has stemmed from Bakiyev's appointment of many of his family members to key government positions. In particular, his younger son, Maxim, was widely detested. Inside Maxim Bakiyev's wrecked and burned mansion a stream of looters and the merely curious trampled over beds of broken glass. On the wall someone had written: "Fuck you". Nearby, they had added: "Death to Maxim!" A couple of fir trees were still left in the beds. But the others had all gone, transplanted – like the rest of Kyrgyzstan – to a new and uncertain future.