Ukraine asked Germany on Wednesday to send a team of doctors to treat Yulia Tymoshenko after the opposition leader went on hunger strike to protest her alleged beating in jail.
The decision marked the latest chapter in a saga that has pitted Tymoshenko against President Viktor Yanukovych for the past two years while unravelling Ukraine's relations with Europe and edging it closer into Russia's fold.
The fiery former Orange Revolution leader -- sentenced in October to seven years for abusing power while premier -- accused "three strong men" of throwing a sheet over her and punching her in the stomach before taking her to a state hospital.
Ukrainian prosecutors immediately denied the charges and accused Tymoshenko of staging a political provocation designed to further damage the current leadership's relations with the European Union.
But the claims sparked a chorus of concern from the EU and Washington while also drawing calls from Moscow for the authorities to show "humanity" in the case.
A Ukrainian foreign ministry spokesman said Kiev had sent an "official request to Germany for its government to assist in the arrival of German doctors from the Charite clinic to examine and treat Yulia Tymoshenko."
The clinic's doctors had paid two prior visits to Tymoshenko's prison in the eastern city of Kharkiv and dismissed claims that she was feigning debilitating back pain that has kept her bed-ridden for months.
But German Foreign Minister Guido Westerwelle indicated Ukraine had set certain conditions in its invitation that required more study from Berlin.
"We are checking if the pre-conditions in the Ukrainian proposal make sense in the context of Tymoshenko's medical treatment," Westerwelle told reporters in Germany.
He added that his government's earlier offer to treat Tymoshenko in a German clinic -- an idea flatly rejected by Ukraine -- was still valid.
Tymoshenko said in a graphic hand-written letter posted by her party's that she began fasting on Friday after being forcibly taken to a state hospital for her back condition that kept her from attending her new trial last week.
The 51-year-old said she "was hit hard with a fist in the stomach" and at one stage "thought the last minutes of my life had come."
The chief local prosecutor conceded Tymoshenko had resisted being taken to hospital -- where she fears being poisoned following a similar attack on former ally and president Viktor Yushchenko in 2004 -- and was moved there by force.
"They took her in their arms, carried her to the vehicle and took her to hospital," prosecutor Hennadiy Tyurin said on Tuesday.
But a report from the Ukrainian parliament's human rights commissioner said a personal inspection on Tuesday showed "a sizable bruise on the lower right side of the abdomen" and other obvious signs of violence on Tymoshenko's body.
Around 15 members of her Batkivschyna (Fatherland) Party said they had staged an all-night parliamentary sit-in and occupied the speaker's podium in order to halt the chamber's morning work.
Some 40 of her supporters on Wednesday had unfurled a banner reading "Yanukovych -- do not kill Tymoshenko" and demanded access to their jailed leader.
An AFP reporter at Tymoshenko's prison later saw seven of Tymoshenko's party members enter the prison building after knocking on its gates and eventually being let in.
Tymoshenko's conviction prevented Ukraine from signing a partnership agreement with the EU which the ex-Soviet nation hopes to secure before eventually winning membership in the bloc.© ANP/AFP