It has appealed to the International Monetary Fund for a $16.4bn loan, which is being given to the country in installments.
Relations between Russia and Ukraine have been strained since the election of Viktor Yuschenko, Ukraine's president, a Western-leaning leader who overcame his pro-Moscow rivals in 2004.
In January, ties deteriorated further over a two-week dispute on gas prices, which resulted in severe shortages of the energy supply across Europe.
A raid on the headquarters of Naftogaz, Ukraine's state gas company, earlier this month, raised concerns over the likelihood of another dispute.
Putin said the raid, by Ukraine's security service, cast doubt over the country's reliability as a gas partner.
"Only God knows what parts of their bodies the people who give these orders are thinking with," he said.