KIEV (Reuters) - Former Ukrainian prime minister Yulia Tymoshenko, already sentenced to seven years in prison for abuse of office, has been charged with tax evasion, theft and concealing foreign currency revenues, the State Tax Administration said on Friday.
Fresh charges indicate she is less likely to go free in the near future despite calls from the West for her release, keeping Ukraine's ties with the European Union strained.
The charges are linked to her activities as the head of gas trading firm, United Energy Systems of Ukraine, it said in a statement, a post she held in the 1990s.
Tymoshenko was found guilty on October 11 of abusing her powers as prime minister in 2009 when she forced through a gas supply deal between Ukrainian state energy firm Naftogaz and Russia's Gazprom.
Tymoshenko has denied all charges against her and said her trial reflected a political vendetta waged by President Viktor Yanukovich, who narrowly beat her in the former Soviet republic's 2010 presidential election.
Echoing her position, the European Union has warned Ukraine it may not sign planned bilateral deals on political association and free trade if Tymoshenko remains in jail.
There is still a possibility that her conviction will be overturned by an appeals court or reclassified as a non-felony by parliament.
However, state prosecutors have said they could launch even more cases against Tymoshenko and were studying her possible involvement in a 1996 contract killing of a parliament deputy -- which her camp has denied.
Supporters of 50-year-old Tymoshenko say her health is deteriorating as she has been in a detention centre since early August and now has trouble walking.
Reporting by Olzhas Auyezov; Editing by Rosalind Russell