A man holds a Ukrainian flag as he stands on Kiev's Independence Square on Monday. Ukraine issued an arrest warrant Monday for ousted president Viktor Yanukovych over the "mass murder" of protesters and appealed for $35 billion in Western aid to pull the crisis-hit country from the brink of economic collapse. Photo: AFP

Ousted president Viktor Yanukovych has been placed on Ukraine's wanted list for mass murder, the acting interior minister said on Monday on his Facebook profile.

"An official case for the mass murder of peaceful citizens has been opened," Arsen Avakov wrote on Facebook. "Yanukovych and other people responsible for this have been declared wanted."

Yanukovych, 63, fled the capital Kiev by helicopter on Friday amid a revolt against his rule after three days of conflict in which more than 80 people were killed. He was in the pro-Russian Crimea region late on Sunday night, Avakov said.

Ukraine has named pro-Western parliamentary speaker Oleksandr Turchynov interim president, a supporter of opposition leader Yulia Tymoshenko.

The appointment was challenged by Russia.

"We do not understand what is going on there. There is a real threat to our interests and to the lives of our citizens," Russian Prime Minister Dmitry Medvedev was quoted by Russian news agencies as saying.

Medvedev said Russia had grave doubts about the legitimacy of those in power in Ukraine following Yanukovych's ouster, saying their recognition by some states was an "aberration."

Meanwhile, Europe is discussing a range of options for short- and longer-term financial assistance to Ukraine, but any comprehensive package is only likely to take shape after elections in May and in coordination with the International Monetary Fund (IMF).

French Foreign Minister Laurent Fabius told reporters in Beijing on Monday that the EU will provide financial support to Ukraine but it also needs support from the IMF.

Fabius said US Secretary of State John Kerry is discussing details of support plans with the German Foreign Minister. Fabius added that he hopes Russia could keep its previous promise to support Ukraine.

Ukraine's finance ministry said on Monday it needed $35 billion to survive 2014 and 2015 and asked for the first payments to be made in the next one to two weeks, possibly alongside a conference of donors.

It is highly unlikely Europe, the US or anyone else would put that much money on the table right away. But smaller bilateral loans, possibly coordinated via the EU, could be used to provide short-term assistance, officials said.