The daughter of former Ukrainian Prime Minister Yulia Tymoshenko says her mother is being ill-treated in prison, but she remains strong in spirit.

Eugenia Tymoshenko testified Wednesday in Washington before a U.S. Senate subcommittee on European affairs at a hearing on Ukraine.

She said that during visits to her mother in prison she has to lift her from the bed and help her walk. Eugenia Tymoshenko said authorities are using sleep deprivation and intimidation to try to break her mother.

“This includes a 24-hour lit room and 24-hour video surveillance. Lately, they (prison authorities) have introduced close-up surveillance cameras so that they can see what she is writing to me, to her husband, to her supporters around the world. They say it is done for her protection, but I doubt it. When she fell unconscious for two hours due to a sudden mysterious loss of blood pressure, no help came and her cellmates tried to revive her for 20 minutes. When the doctor arrived, they didn't even call an ambulance.”

Eugenia Tymoshenko said the family learned about the incident three days later, even though her mother could have died that night. She said authorities are trying to weaken her mother to get her to publicly ask President Viktor Yanukovych for a pardon.

Yulia Tymoshenko helped former Ukrainian President Viktor Yushchenko defeat Viktor Yanukovich in the 2004 presidential election. She competed against Mr. Yanukovych in the 2010 election, which he won by a convincing margin.

After Mr. Yanukovych became president, Ukrainian prosecutors started several criminal proceedings against Tymoshenko. Late last year, she was found guilty of abuse of power in a 2009 gas deal with Russia and was sentenced to seven years in prison. She denied the charges, saying the process was politically motivated.

The younger Tymoshenko, a businesswoman in her own right, told the group of U.S. senators that she witnessed what she called her mother's “show trial” in which she said the judges and prosecutors were acting as the president's puppets.

Eugenia Tymoshenko insisted that her mother was fighting corruption and introducing transparency into Ukraine's gas trade with Russia. She said her mother was alone in that fight.

“I have no doubts that the verdict against my mother was sought and approved by President Viktor Yanukovich. She is according to the recent polls his main political opponent and more popular than him. But I don't want you to think that this is only about my mother. It is not. Others are being repressed and unjustly imprisoned. What we are witnessing in Ukraine is such a twisting of the rule of law that it isn't possible to distinguish illegality from legality. It's hard to see the line between the law and the abuse of law.”

The United States and European Union have called the prosecution of Ms. Tymoshenko “selective prosecution of political opponents.”

At the end of December, she was transferred to a penal colony in the northeastern city of Kharkiv.

Ms. Tymoshenko's husband Oleksandr was granted asylum in the Czech Republic earlier this year.

During the hearing on Ukraine Wednesday in the U.S. Senate, participants noted that Ukraine's democratic progress went backward in the last few years and they discussed ways of getting it back on track.