Updated

Ukraine's president proposed an amnesty Friday for all those facing criminal charges in the country's wave of anti-government demonstrations, but the gesture did little to mollify opposition leaders driving the protests.

The opposition, their determination bolstered by the stand-down of riot police in a pair of confrontations this week, grudgingly decided at the last minute to attend the round-table talks with Viktor Yanukovych.

The round table was made up of the country's main opposition leaders, along with student, religious and union representatives. It also included former Presidents Viktor Yushchenko, Leonid Kuchma and Leonid Kravchuk.

The opposition met his amnesty proposal with demands that the government step down, and for early parliamentary and presidential elections to be held.

The opposition also wasn't heartened by new official promises that Ukraine intends to sign a trade and political pact with the European Union. Yanukovych's refusal to sign the agreement last month set off the protests.

The round table was an effort to find a way out of the three-week old crisis that threatens Yanukovych's leadership. But with the sides still far apart, Kiev was girding for huge demonstrations this weekend.

The opposition has called for a vast turnout Sunday. Rallies on the previous two Sundays drew hundreds of thousands of protesters. That same day, Yanukovych's Party of Regions has called for a pro-government demonstration that it claims will bring 200,000 people to Kiev.

The prospect of a huge cadre of government-backers in the vicinity of protesters has raised fears of provocations that would induce riot police to crack down brutally. The opposition blames provocateurs for a previous violent demonstration dispersal.

"We are really afraid and we know that there will be very many provocations," world superheavyweight boxing champion and opposition leader Vitali Klitschko told The Associated Press.

Officials have said there will be no action taken against peaceful protests, but those assurances are shadowed by the pre-dawn events of Wednesday, when thousands of riot police converged on Independence Square, where a large protesters' tent camp has been set up and demonstrators gather around the clock.

The police tore down some barricades and tents, but demonstrators stood their ground and police left after sunrise. A smaller police contingent scuffled with demonstrators who have occupied the nearby city hall, but also retreated.

It remained unclear whether the police left because of the protesters' resistance or if they had been ordered only to try to intimidate the demonstrators rather than drive them out. Some opposition figures suggest the stand-down showed Yanukovych was losing the loyalty of the country's extensive security forces.

Yanukovych said he believed an amnesty should be declared for those arrested in the protests "in order to give guarantees that the process of confrontation will stop."

"I am outraged by the radical actions on both sides ... from the side of provocateurs and from the side of the security forces, which have not always behaved properly," he added.

Also looming in the crisis is continued anxiety about a Tuesday meeting between Yanukovych and Russian President Vladimir Putin. Russia strongly opposes Ukraine's closer ties with the EU and wants it to join a customs union, also including Belarus and Kazakhstan, which opponents denounce as effectively a reconstitution of the Soviet Union. Concern persists that Yanukovych could sign on to the customs union on Tuesday.

Prime Minister Mykola Azarov said Friday the presidents are expected to sign agreements resolving "the overwhelming majority of trade disputes" with Russia, but did not mention the customs union.

On Thursday, after meeting with EU officials in Brussels and receiving promises of more aid from the bloc, Deputy Prime Minister Serhiy Arbuzov said Ukraine aims to sign the agreement soon, once unspecified issues are worked out.

The opposition was dismissive.

"They had a chance to sign just two weeks ago and why hasn't that happened? It is just a game," Klitschko said.

The economically troubled nation of 46 million is divided over the EU deal. Many people in eastern Ukraine, the country's industrial heartland and Yanukovych's support base, are against the protesters in Kiev and want the country to have closer economic ties with Russia.