The Ukraine crisis should be resolved through continued talks of the European Union (EU), the United States, Russia and Ukraine, Prime Minister Arseny Yatsenyuk said Thursday.

"Regarding further format of negotiations, I remain a supporter of negotiations in an exclusive 'Geneva format,'" Ukrinform news agency quoted Yatsenyuk as saying at a government meeting.

On April 17 in Geneva, Ukraine, Russia, the United States and the EU agreed to disarm illegal groups and initiate a national dialogue on constitutional reform in Ukraine.

Meanwhile, Ukraine launched a months-long military operation in the eastern part of the country, accusing separatists of constantly violating agreements with the government. Kiev has also blamed Russia for supporting the militants.

Speaking of the fresh sanctions Washington and Brussels decided to impose against Russia, Yatsenyuk said Kiev had observed "unity" among its Western partners.

The prime minister added the sanctions were Russia's costs for what he called "military aggression, arms supplies and financing of the bandits."

On Wednesday, EU leaders agreed to impose new sanctions on Russian companies allegedly helping to destabilize Ukraine.

A few hours before Brussels' announcement, the United States announced the most wide-ranging sanctions yet on Russia, targeting key institutions including Gazprombank and Rosneft, as well as other energy and defense companies.

In Moscow, the Russian Foreign Ministry said Thursday that Russia would retaliate "asymmetrically but painfully," after the United States and the European Union (EU) announced fresh sanctions against the country.

"We are not going to tolerate blackmail and reserve the right to take measures in response," the Russian Foreign Ministry said in a statement.

Also on Thursday, Russian Prime Minister Dmitry Medvedev said that in light of fresh sanctions from the West, Moscow will shift the focus of budget spending toward more generous support for the defense sector.