Ukraine's parliament is considering Wednesday an amnesty for scores of people arrested during the past two months of recent political protests in Kyiv.
Ukraine's embattled President Viktor Yanukovych has said amnesty is only possible if the protesters vacate the government buildings they are occupying and remove their barricades from the streets.
Opposition leader Arseniy Yatsenyuk on Wednesday called that condition "unacceptable."
On Tuesday, Mr. Yanukovych accepted the resignation of Prime Minister Mykola Azarov -- a key demand of the protesters, who have occupied central Kyiv for weeks. Mr. Azarov's first deputy, Serhiy Arbuzov, has been named acting prime minister.
Additionally, Mr. Yanukovych signed legislation repealing anti-protest measures enacted earlier this month to crush the protests.
Despite the concessions, opposition leaders are looking for more, including new presidential elections.
In Washington, U.S. Vice President Joe Biden welcomed Tuesday's concessions and voiced support for amnesty measures to ease the two-month crisis.
Opposition supporters took to the streets in late November when Mr. Yanukovych backed out of a trade deal with the European Union in favor of closer ties to Russia that include a $15 billion Russian bailout.
In Brussels Tuesday, Russian President Vladimir Putin told European Union leaders that Moscow will keep its loan promise to cash-poor Ukraine and provide steep natural gas discounts -- even if the opposition comes to power.
However, Russian First Deputy Prime Minister Igor Shuvalov, who also was attending the Brussels summit, said Moscow probably would re-examine its pledges if a new Kyiv government were to announce "different priorities."