BERLIN -- Former Ukrainian Prime Minister Yulia Tymoshenko's chronic back ailment has improved somewhat, but she is far from cured and the conditions at a hospital in her homeland are making treatment very difficult, German doctors said Tuesday.

The case of Tymoshenko, who was sentenced to seven years in prison for abuse of office, has become a political hot potato as Ukraine prepares to co-host football's European Championship with Poland. France's government says it will boycott matches held in Ukraine because of Tymoshenko's case.

Officials in Berlin have tried to persuade Ukraine to allow Tymoshenko to travel to Germany for treatment. But Karl Max Einhaeupl, the head of Berlin's Charite hospital, said he sees "no tendency in Ukraine to allow her to leave" for treatment.

Einhaeupl and colleagues from Charite have examined her and supervised her treatment at a hospital in Kharkiv, where she has been serving her sentence, in recent weeks.

"The medical condition has improved – she is more mobile, she is moving around at least a few hours a day," Einhaeupl told reporters. "The pain is a little bit less than at the beginning of the treatment, but it's not gone at all."

Tymoshenko's deep distrust of Ukrainian officials and government-appointed doctors hasn't helped and was fed, for example, by an incident in which her medical records were shown on television, he said.

Her treatment at the hospital is "under constant surveillance, by video cameras and by guards," he added.

The German doctors insisted on the cameras being taped over during visits, but Tymoshenko fears that there may be more, hidden cameras. Doctors also pressed for authorities to uncover one hospital room's windows for a short time each day and allow in daylight.

"I think I can say that ... Mrs. Tymoshenko has great trust in the doctors from Germany, but we are never alone with her – there is always someone there," not least a second patient in the same room, Einhaeupl said.

"It is proving to be very difficult and, in the end, it is impossible to predict whether, under these conditions, we can really bring about a cure," he said.

Einhaeupl said Tymoshenko has raised the possibility of being transferred to Kiev, which the German doctors would welcome as it would make it easier for them to travel to treat her. Putting Tymoshenko under house arrest also would make matters easier, he added.

"She is afraid that people will harm her," Einhaeupl said. "That's the reason she refuses every injection or everything which is invasive."

Tymoshenko won't allow doctors to take blood because she is afraid of an infection, he said.

Tymoshenko's case has significantly strained Kiev's relations with the West. Tymoshenko claims that President Viktor Yanukovych, a longtime rival who narrowly defeated her in the 2010 presidential election, is seeking to get rid of political opponents.

Yanukovych says his government is merely fighting corruption.

Tymoshenko was given a seven-year prison sentence last October on charges of abuse of office while conducting natural gas import negotiations with Russia in 2009. The West condemned the verdict as politically motivated and pressed Ukraine to free her.

The former premier denies the charges and accuses Yanukovych of throwing her in jail in order to bar her from parliamentary elections.

She also faces other criminal charges and investigations. Three senior members of her government have been imprisoned on corruption and abuse-of-office charges.

In April and May, Tymoshenko staged a nearly three-week hunger strike to protest alleged abuse. Photos of bruises on her body that appeared to corroborate her claim that she was beaten by prison officials shocked the West.

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