KIEV - Ukraine's jailed opposition leader Yulia Tymoshenko, whose plight in prison has soured relations between the country's leadership and the West, was moved to a local hospital on Wednesday in a high-security police convoy.

Ukrainian President Viktor Yanukovich has faced growing criticism over the conviction of Tymoshenko - and the authorities' refusal to let her travel abroad for treatment for chronic back pain.

Her transfer from prison in the eastern city of Kharkiv to a nearby hospital for treatment under the supervision of German doctors was worked out last week in a compromise.

But Wednesday's early morning transfer seemed unlikely to relieve pressure on Yanukovich who has been thrown on the back-foot by sharp Western criticism of his treatment of his rival.

Tymoshenko, 51, a former prime minister, was jailed last October for seven years for alleged abuse of power while in office, a charge she denied.

She says she is the victim of a vendetta by Yanukovich who narrowly beat her for the presidency in February 2010. The European Union and the United States have condemned her trial and sentencing as politically motivated and called for her to be released.

Outcry in the West intensified after Tymoshenko said she had been beaten in jail and went on hunger strike on April 20 in protest against alleged ill-treatment. Authorities have denied she was mistreated.

Her daughter, Yevgenia, said on Tuesday her mother had agreed to end her hunger strike under the supervision of a German doctor in a local hospital.

Reuters eyewitnesses in Kharkiv said Tymoshenko was brought to a side entrance of the hospital by ambulance on Wednesday morning in a heavily guarded convoy that included several police cars.

Two lines of white-coated hospital staff shielded her as she was carried into the hospital on a stretcher, preventing journalists and onlookers catching a glimpse of her.

A few supporters nearby shouted out "Freedom for Yulia!"

The state prison service, in a statement, confirmed she had been moved to hospital "for the course of rehabilitation recommended by the international medical commission".