A Ukrainian appeals court has upheld the conviction of and seven-year jail sentence for former prime minister Yulia Tymoshenko.

Ms. Tymoshenko was convicted of abusing her authority in a 2009 gas deal with Russia that her opponents say was too beneficial for Moscow. She also faces numerous other charges.

The former prime minister and opposition leader has denied any wrongdoing and boycotted the appeals trial — saying she did not want to take part in what she called a “shameful process.”

Ms. Tymoshenko and her attorneys on Thursday filed a case with the European Court of Human Rights, which has promised to give it priority.

On Wednesday, Ukrainian President Viktor Yanukovych said he does not oppose her release but that he cannot interfere in the legal process.

The trial has affected Ukraine's ties with the European Union, which Kyiv seeks to join. The EU on Monday said it will not sign a landmark political and trade cooperation agreement with Ukraine until it resolves Ms. Tymoshenko's case.

Ms. Tymoshenko has described her trial as “a political lynching” aimed at allowing President Yanukovych to rid himself of a political rival. She had been expected to be the main opposition candidate in an election next year, but is not eligible to run if her conviction is upheld.

Mr. Yanukovych has denied her accusation.

The United States, the European Union and human rights groups have condemned the charges against Ms. Tymoshenko as politically motivated.