Ukraine's former prime minister is on trial for alleged abuse of power.

Yulia Tymoshenko, now a top opposition leader, went on trial Friday in the capital, Kiev.

She has been charged with abuse of office in signing a deal with Moscow to buy Russian natural gas at prices investigators said were too high.

Ms. Tymoshenko has maintained her innocence and says the charges against her are part of a politically motivated campaign by Ukrainian President Viktor Yanukovych to crush the opposition. Several officials who served in her government are in prison.

Mr. Yanukovych narrowly defeated Ms. Tymoshenko in presidential elections last year.