In a statement released on Tuesday, Russia's Foreign Ministry dismissed as illegal US efforts to provide financial aid for the interim Ukrainian government.
According to the statement, the move goes beyond the US legal framework because it would fund an illegitimate regime.
"By all criteria, issuing funding to an illegitimate regime that seized power by force is unlawful and goes beyond the framework of the American legal system," the statement noted.
It also warned Washington about the consequences of "unconditionally indulging radical elements" among Ukraine’s new leadership.
On the same day, Russia’s Foreign Minister Sergey Lavrov talked with his US counterpart John Kerry about the efforts to bring peace and calm to Ukraine’s now-volatile Crimea region.
The two agreed to continue bilateral talks. Lavrov told Kerry that any solution should consider interests of all Ukrainians and respect the Crimeans' right to determine their future.
For his part, Kerry condemned as unacceptable the moves by Russian forces to take matters into their own hands in Ukraine.
Meanwhile, Crimean lawmakers endorsed a declaration of independence, which was required by law to hold a secession referendum on March 16.
The Crimean parliament voted on Tuesday for the region to declare itself an independent state if its residents agree to split off from Ukraine and join neighboring Russia in the referendum.
The declaration achieved 78 votes in favor out of 81 assembly members present in the 100-member parliament.
Russia has welcomed the Crimean assembly’s declaration of independence from Ukraine, describing it as an “absolutely lawful” measure.