KIEV, Ukraine, Aug. 21 (UPI) -- Ukrainian Prime Minister Yulia Tymoshenko interrupted a vacation to counter allegations of advocating Russian interests in her country, officials said Thursday.

President Viktor Yushchenko Monday accused his prime minister of negotiating a secret deal with Russia to back her bid for the presidency. Tymoshenko said she had made no such deal, arguing the move would fracture the government, the Ukrainian Journal reported.

The allegations come as Yushchenko backed a plan to reverse the flow of oil from the Odessa-Brody pipeline to its original direction toward European markets.

The pipeline had moved from Brody in western Ukraine to the Black Sea port of Odessa, viewed as bolstering Russia's hold on the regional energy market.

Tymoshenko in July opposed a decision to transport oil through the pipeline in its intended direction, and in May she blocked an oil exploration deal with U.S. oil company Vanco Energy.