Ukraine on Friday transferred jailed former prime minister Yulia Tymoshenko from a Kiev detention centre to a prison in the eastern Kharkiv region to serve her out seven year sentence.

Her transfer came after a Kiev court last week rejected an appeal against her conviction and despite claims by her supporters that the opposition leader is now so frail she cannot walk.

"At 8:00 am (0600 GMT) Yulia Tymoshenko was transferred to a prison in the Kharkiv region to serve her sentence," Ukraine's prison service said in a statement, adding that a "comfortable minibus" was used for the transfer.

Tymoshenko was sentenced this year to seven years in jail after being convicted of abuse of power while in office, a verdict she claims was ordered by President Viktor Yanukovych and has severely damaged ties with the EU.

Her lawyer Sergiy Vlasenko said she was taken in a prison van and with her arms held by guards from the Kiev detention centre for the journey.

The prisons service however denied claims in the online Ukrainska Pravda newspaper that Tymoshenko had been transferred in a wheelchair and also said that her minibus had "full amenities" including a lavatory and a wash basin. Her belongings were taken in a separate vehicle in 12 suitcases, it added.

The prisons service did not specify to which prison in the Kharkiv region Tymoshenko was taken. But her press service said it was the Kachanivska womens' prison, one of the largest of its type in Ukraine.

Her new prison is officially described as a place where prisoners serve out their sentences, while Kiev's Lukyanovsky jail where she was held until now is formally a detention centre for prisoners awaiting trial.

The leader of the 2004 Orange Revolution was sentenced in October for abuse of power while prime minister in a case taken months after she lost a close election to Yanukovych.

Tymoshenko's conviction was followed almost immediately by charges of financial crimes, allegedly committed while she was head of the state power company in the 1990s, that could keep her in prison even if the original case against her is overturned.

Her jailing was the cause of Ukraine failing to clinch an Association Agreement with the European Union as planned this year. EU officials have warned the case has endangered Kiev's ambitions of one day joining the bloc.

The United States raised concerns about the rejection of her appeal. The State Department said the court "did not address concerns about democracy and rule of law raised in the initial trial and sentencing."

Despite urgent calls for her release, Yanukovych has sought to stay aloof from the whole affair, insisting he has no right to interfere in the legal process.