Jailed Ukrainian ex-premier Yulia Timoshenko must spend at least one more month in hospital, a prison medical commission ruled on Tuesday, dpa reported.
Ukrainian vice Health Minister Raisa Moiseyenko made the announcement based on recommendations of local and German medical specialists examining Tymoshenko, who is serving a seven-year jail sentence in the eastern city Kharkiv.
Tymoshenko, the leader of Ukraine's political opposition, is suffering from back problems. A doctor from Berlin's Charite hospital was among the examiners, Moiseyenko said, according to an Unian news agency report.
Lutz Harms, the Chariete doctor, told reporters at the Kharkiv detention centre said Tymoshenko's condition was slowly improving, but she still was unable to walk without difficulty.
"There has been progress ... but she still suffers pain," Harms said, in comments reported by the Interfax news agency.
Warder searches of her living quarters and other psychologically-stressful incidents connected with Tymoshenko's imprisonment, were slowing her recovery, he said.
Moiseyenko said Tymoshenko might be hospitalised a month or more before she recovered fully.
A Kiev court in October found Tymoshenko guilty of abuse of office for a natural gas deal signed with Russia while she headed Ukraine's government in 2009.
A leader of Ukraine's 2004 pro-democracy Orange Revolution, Tymoshekno has denied wrongdoing and said she is the victim of judicial persecution.
European Union nations have criticized Tymosheko's imprisonment and delayed an economic cooperation agreement with Kiev because of worries about rule of law in Ukraine.
Ukrainian President Viktor Yanukovych has said he supports rule of law, but that Tymoshenko was tried and found guilty in a fair court, and now should serve her sentence.