Russia has urged Ukrainian opposition leaders to end their campaign of "ultimatums and threats" and to step up negotiations with the government.
Russia\’s foreign ministry said Moscow was concerned by activists\’ attempts to "inflame" the situation.
Russia promised a $15bn aid package to Ukraine last year, but has indicated the next tranche will not be given until a new government is formed, following the resignation of the prime minister and cabinet last week.
On Sunday, thousands of people joined a new rally in the centre of the capital, Kiev, with opposition leaders calling for international help.
The Russian foreign ministry denounced their actions in a statement on Monday, saying they were particularly "puzzling" in the wake of a summit held in Munich last week on Ukraine\’s future.
"We expect the opposition in Ukraine to avoid threats and ultimatums and step up dialogue with the authorities in order to finding a constitutional way out of the country\’s deep crisis," the foreign ministry said.
Western politicians are returning to Ukraine this week to resolve the political crisis that has gripped the country for months, with the US saying it is in preliminary discussions to provide financial aid to the protest-hit country.
According to the news agency AFP, the European Union\’s head of foreign policy, Catherine Ashton, is in Kiev to meet with the government and the opposition to try to resolve the stalemate between the two sides.
US Assistant Secretary of State for European and Eurasian Affairs, Victoria Nuland, is also travelling to the Ukrainian capital this week.
In Washington a US State Department spokesman said on Monday that the US was in "preliminary" talks about putting together a financial aid package for Ukraine.
Jen Psaki said: "Let me be clear, this is at a very preliminary stage. We are consulting with the EU … and other partners about the support Ukraine may need after a new technical government is formed."
Opposition leader Arseniy Yatsenyuk has asked for $20bn, a similar sized package to the one promised by Russia that is now on hold.
Meanwhile, Ukraine\’s President Viktor Yanukovich, who joined office on Monday after a brief illness, criticised mass protests against his government as "extremism".
Yanukovich criticised the anti-government movement as "radicalism and incitement to hatred behind which there is a struggle for power".
The renewed attempts to resolve the crisis come as disagreement and confusion emerged among activists about the way forward.
Some anti-government activists have agreed with the police to demolish a major barricade and end their two-month occupation of City Hall in exchange for the amnesty of all arrested protesters.
According to a report published on the Korrespondent news website on Monday, Andrei Paruby, from the opposition Batkivshchyna party, and representatives from other activist groups met Aleksand Yakimenko, the head of Security Service of Ukraine, and Viktor Dubovik, the first deputy of minister of internal affairs, on Friday.
Source: Al Jazeera and agencies