TBILISI (Reuters) - Georgian President Eduard Shevardnadze declared a state of emergency Saturday after opposition protesters proclaiming a "velvet revolution" stormed parliament, forcing the veteran leader to flee.

In scenes reminiscent of the "people power" protests in eastern Europe in 1989, tens of thousands of Georgians demanding Shevardnadze quit power took to the streets of the capital Tbilisi while troops stood aside.

As Georgia plunged deeper into crisis, the main opposition leader said Shevardnadze, whom he accuses of rigging elections and ruining the country through years of misrule, could stay on only if it was to call early fresh elections.

"The victory has almost been accomplished," Mikhail Saakashvili told thousands of supporters outside parliament.

He told CNN television: "We won't accept anything short of (an early election). If he announces for himself some transitional period for new presidential elections, that's fine. If he wants to call (them), we can still negotiate on that.

"It's a corrupt regime, he stole the election, he ignored the will of the people -- What else do you want us to do? We told him: 'Your time is up. Either you submit to the will of the people, or you're out.' And he's out."

"It's a bloodless, a velvet revolution," he said, recalling Czechoslovakia's peaceful overthrow of communism in 1989.

And he backed fellow opposition leader and parliamentary speaker Nino Burdzhanadze who declared she was taking on the functions of the president in the Caucasus state of five million until the crisis was resolved.

Culminating two weeks of street demonstrations, protesters had thronged into parliament where they clambered onto the podium, dancing, shouting and waving national flags in delight.

PRESIDENT FLEES FROM BUILDING

Shevardnadze, 75, had been addressing the inaugural session of a parliament elected on November 2, but had to flee to his home on the outskirts of the city where he was protected by bodyguards and special forces.

"This is an attempt at a coup d'etat and an attempt to overthrow the president," he told reporters in his garden.

"I cannot do it any other way now. I'm declaring a state of emergency. This is a special order and the Defense Ministry as well as the Interior Ministry will be involved in it. And we will restore order."

"Looking at these people it is possible a civil war could break out. I have allowed too much liberalism...It is a crime against the people and the motherland. I won't allow it."

Four armored personnel carriers, more than 10 buses and minibuses with soldiers later took up positions outside Georgia's Interior Ministry.

Shevardnadze formally has another year and a half in office.

"This is a parliament. We are not in the street. Let all Georgia see what is happening," he had said in parliament amid chaotic scenes before his bodyguards hustled him away.

Fistfights broke out for a time between his supporters and opposition.

The Kremlin said Russian Foreign Minister Igor Ivanov would go to Georgia after President Vladimir Putin consulted other leaders of ex-Soviet states on the situation, but did not say when.

After the state of emergency, the United States urged both sides to refrain from violence and start a dialogue.

OPPOSITION SAYS POLL RIGGED

Opposition leaders accuse Shevardnadze of dragging Georgia into ruin through years of misrule.

Burdzhanadze told reporters: "I, as chairman of the Georgian parliament, in accordance with the constitution, will take on the functions of the president until such time as it becomes clear whether he has the ability to continue."

She is the speaker of the former parliament and it was not clear whether she officially still held the position.

A pro-president rally vanished as soon as the opposition took the parliament.

Most Shevardnadze supporters had been brought by bus or train from the Black Sea Adzhara region, whose hardline leader, Aslan Abashidze, has made a loose alliance with Shevardnadze.

Georgia's communist party boss and leader for nearly all the post-Soviet period has been uncompromising in his stance, refusing to be pushed from office by the demonstrators.

Any trouble could threaten a planned oil pipeline through Georgia from neighboring Azerbaijan to Turkey.

Washington has called for an independent investigation into what it said was massive fraud at the election.