Ukraine's parliament is considering 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. 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.
Meanwhile, former Ukrainian president Leonid Kravchuk warned Ukraine is on "the brink of civil war," adding there are "parallel authorities in the country and there is a de-facto uprising."
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.
On Wednesday, Russian President Vladimir Putin repeated a promise he made a day earlier that even if the opposition comes to power in Ukraine, Moscow will make good on its pledge to provide the $15 billion loan along with substantial natural gas discounts.
"I would ask our government to fulfill all our financial agreements in full," he said.
But Russian Economics Minister Alexei Ulyukayev said Wednesday that the "schedules and parameters" of financial aid to Ukraine required "further discussion" with Kyiv and "consideration of the restructuring" of Ukraine's government.
On Tuesday, Russian First Deputy Prime Minister Igor Shuvalov said Moscow probably would re-examine its pledges if a new Ukrainian government were to announce "different priorities."
The Kremlin said in a statement Wednesday that Mr. Putin had stressed during a telephone conversation with German Chancellor Angela Merkel that "any outside interference" in Ukraine is "unacceptable."