Ukraine's high court has rejected former prime minister Yulia Tymoshenko's appeal against her conviction on charges of abuse of office.

A judge said Wednesday the court could not approve the appeal by Ms. Tymoshenko, who is serving a seven-year sentence.

The ruling comes a day after her lawyers argued before the European Court for Human Rights that she was held before her trial illegally and under inhumane conditions.

The charges are linked to a natural gas deal she brokered with Russia in 2009 while serving as prime minister.

She faces separate charges of embezzlement and tax evasion. A trial in that case is expected to resume September 11.

Ms. Tymoshenko was a co-leader of the 2004 pro-democracy Orange Revolution. She says both cases are part of a political vendetta against her by President Viktor Yanukovych, who narrowly defeated her in a 2010 vote.