Talks between the two countries' prime ministers yesterday failed to resolve the gas issue.
Yushchenko said if Russia was going to take such an inflexible position concerning its gas exports then Ukraine was justified in taking a hard line on Russia's use of Ukrainian ports in the Crimea.
"We are coming to an understanding that all our economic relations [with Russia] should be in accordance with international standards, with European standards. Therefore, when we are talking about the financial aspects of leasing Ukrainian ports and land [to Russia] and the temporary stationing of Russia's Black Sea Fleet in Sevastopol, we are undoubtedly talking about a similar approach," Yushchenko said.
Russia currently pays some $98 million annually for renting the naval base at Sevastopol.