Ukraine's leader called for the opposition to yield some ground ahead of a new mass demonstration on Sunday, after authorities released all protesters arrested in the anti-government unrest.

The United States welcomed the prisoner release as an "important step to de-escalate tensions" after more than two months of political crisis as protesters seek to oust President Viktor Yanukovych.

However the government concession was unlikely to appease the protesters occupying Kiev's central Independence Square and nearby buildings who are demanding a new, pro-Western government.

"I don't want to wage war," Yanukovych said in a televised interview.

"I want to safeguard the state and resume a stable development. We are asking the opposition to also make concessions."

Anti-government protests have raged since November when Yanukovych rejected an EU trade pact in favour of closer ties with Russia, angering pro-EU parts of the population.

Yanukovych made several concessions after protests turned deadly at the end of January, dismissing the government and signing a law agreeing to amnesty all detainees.

But he set one condition -- that protesters evacuate all public buildings they are occupying, such as Kiev city hall next to Independence Square.

On Friday, Ukraine's attorney general Viktor Pshonka announced that "234 people were arrested between December 26 and February 2. None of them are in custody anymore".

He added that if the amnesty law's condition was met, all charges -- some carrying sentences of up to 15 years in jail -- would be dropped over a month starting from February 18.

The opposition has agreed to vacate "part" of Grouchevsky street, where government and parliament buildings are located, to allow traffic to move freely.

"This does not mean we are vacating the (occupied) premises or lifting the barricades," said opposition representative Andrii Dzyndzia.

US State Department deputy spokeswoman Marie Harf urged both sides to continue to de-escalate tensions and find a compromise to the crisis.

"The next step in this process should be the formation of a multiparty technical government, with genuine power-sharing and responsibility," she said.

Harf called on the government to stop all arrests and prosecutions against demonstrators and activists, adding Washington was "gravely concerned" over increasing intimidation of the media and civil society organisations.

The protest movement shows no sign of dying down, with protesters rebuilding and fortifying barricades on the square to keep riot police out of their anti-government enclave.

"The only subject of negotiation with Yanukovych are the conditions of his departure," jailed opposition leader Yulia Tymoshenko said in an interview with weekly Dzerkalo Tyzhnia.

The mass demonstration on Sunday will be the 11th since the protest movement erupted, and will kick off at midday (1000 GMT) at the heart of the sprawling, barricaded tent city on Independence Square.

In Kiev's occupied city hall, where 600 to 700 demonstrators are camping out, adorning the building with photos and satirical pictures, Commander Ruslan Andreiko of the protest movement reiterated that Yanukovych had to step down.

"I believe the only condition for people to free the Maidan (Independence Square) is the resignation of President Yanukovych, followed by early presidential elections," he said, as protesters with various ailments consulted volunteer doctors nearby.

The city council is run with military precision, kept clean by countless volunteers who also work in the kitchen or at a makeshift pharmacy to dole out donated medicine, and they show no sign of wanting to move out.

The opposition has also demanded that a new pro-West government be established.

Arseniy Yatsenyuk, an opposition leader who has been offered the premiership, has said he may accept if other opposition members get key government positions.

He also wants the constitution to be amended to reduce presidential powers in favour of parliament and government, but debate on this reform does not seem to be progressing.

Meanwhile the crisis continued to stoke wider tensions between Russia and Western nations tussling over Ukraine's future, with Moscow accusing the European Union Friday of trying to extend its "sphere of influence" in the country.

Several opposition leaders were also expected to travel to Berlin on Monday to meet with German Chancellor Angela Merkel.

"Pressuring Ukraine in one direction, while warning that it faces an 'either-or' choice -- either the EU or Russia -- is essentially trying to create a sphere of influence," Russian Foreign Minister Sergei Lavrov said at a press conference with his visiting German counterpart Frank-Walter Steinmeier.

"This is not a geopolitical chess game taking place in Ukraine. We have to allow the Ukrainians to find their own path," Steinmeier retorted.