The report comes a day after Gazprom, Russia's gas monopoly, announced that Ukraine had $2.4 billion in outstanding debt for gas supplies, and President Dmitry Medvedev ordered the company to urgently recover the debt.
Addressing a National Security Council session, Yushchenko blamed Prime Minister Yulia Tymoshenko, his former "orange revolution" ally, for running up the debt, the agency said.
Ukraine currently pays $179.5 per 1,000 cubic meters for gas imported from Russia or via Russian territory. Until recently, the gas was sold via the Swiss trader RosUkrEnergo, in which Gazprom holds 50%.
RosUkrEnergo was established in July 2004 on a parity basis between Gazprom and Ukraine's national oil and gas company Naftogaz as the exclusive supplier of natural gas to Ukraine.
Naftogaz denied on Friday that it had any outstanding debt to Gazprom, and urged media, politicians and analysts to "cease speculation on the issue, as it could affect negotiations on gas supplies to Ukraine in 2009."
At a meeting with Gazprom CEO Alexei Miller on Thursday, the Russian president stressed the importance of receiving full payment for gas supplies given the financial pressure on Russia due to the credit crunch and falling oil prices.
Miller has said the price of the natural gas Gazprom sells to Ukraine could rise to over $400 per 1,000 cubic meters as of the start of next year.
