The Ukrainian Prosecutor General's Office has reopened a criminal case against opposition leader and former prime minister Yulia Tymoshenko, charging her with embezzlement of state funds and tax evasion.

Ms. Tymoshenko was sentenced to seven years in prison earlier this month for exceeding her powers as prime minister when she signed a 2009 gas deal with Russia that her opponents say was overly beneficial to Russia. The United States and the European Union have condemned the trial as politically motivated.

The revived charges allege Ms. Tymoshenko embezzled around $3 million and evaded $2.5 million in taxes when she headed a Ukrainian energy company more than 10 years ago. The 50-year-old Tymoshenko also faces other corruption investigations.

The latest probes are a setback to efforts to free Ms. Tymoshenko from prison. President Viktor Yanukovych has said her fate may be determined by proposed amendments to Ukraine's criminal code that would decriminalize her abuse-of-office offense. He said such amendments will be considered by an appeals court if they are approved before her appeals process begins.

Ms. Tymoshenko's lawyers say they will appeal the verdict. She has repeatedly denied the charges and described her trial as “a political lynching,” aimed at allowing President Yanukovych to rid himself of a political rival.

The former prime minister was expected to be the main opposition candidate in a parliamentary election next year, but she is not eligible to run if the conviction is upheld.

She is one of about 400 officials under investigation for crimes allegedly committed while in office. Critics have noted that the only cases to come to trial involve political opposition figures.

Ms. Tymoshenko rose to fame in 2004 as a leader of Ukraine's “Orange Revolution” street protests, which forced the Supreme Court to toss out the results of a disputed election won by Mr. Yanukovych.