A German doctor has arrived in Ukraine to help treat the severe back condition of jailed former Prime Minister Yulia Tymoshenko.

Tymoshenko, who is Ukraine's top opposition politician, is serving a seven-year sentence on charges of abuse of office. Her imprisonment has been condemned as politically motivated by the West. She has been on a hunger strike for some two weeks to protest what she claims was a beating by prison officials.

Tymoshenko has tentatively agreed to be treated at a hospital in the eastern Ukrainian city of Kharkiv where she is imprisoned, if the treatment is under the supervision of a doctor from Berlin's Charite clinic. The doctor arrived in Kharkiv late Monday.

Germany has been at the forefront of Europe's critical stance on Ukraine's handling of the Tymoshenko case.