The daughter of former Ukrainian Prime Minister Yulia Tymoshenko says her mother is being tortured in prison.
Tymoshenko is serving a 7-year sentence on charges of abuse of office in a case the West has condemned as politically motivated.
Daughter Eugenia Tymoshenko told the Senate Foreign Relations Committee on Wednesday that prison authorities have intentionally caused her mother sleep deprivation.
"My mother has been illegally imprisoned, maltreated and humiliated for six months by the regime which is trying to break her," according to her prepared testimony.
Eugenia Tymoshenko said her mother is constantly kept in a lit cell under video surveillance and recently fell unconscious from a "mysterious loss of blood pressure."
Prison authorities have said she merely felt dizzy.
Eugenia Tymoshenko said her mother has serious health problems that have gone untreated.
The embassy of Ukraine had no comment Wednesday.
"Her continued imprisonment on dubious, politically motivated charges is unacceptable and antithetical to a free and open system," Sen. Jeanne Shaheen, D-N.H., who chaired the hearing.
Tymoshenko was convicted in October of overstepping her authority while negotiating a natural gas contract with Russia in 2009. Her allies have accused President Viktor Yanukovych of orchestrating the charges as political vengeance.
The U.S. and the European Union have sharply criticized Tymoshenko's imprisonment and demanded her release. The EU has refused to sign a key partnership deal with Kiev over the case.
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