Tensions between Berlin and Kiev reached new heights after German media reported Chancellor Angela Merkel could boycott matches held in Ukraine unless Tymoshenko is released.
Merkel is seriously considering banning the cabinet from attending Germany's games in Ukraine during the championship in June if Tymoshenko is still in prison then, Der Spiegel magazine reported on Sunday.
Tymoshenko, 51, went on hunger strike on April 20 saying she was in chronic pain and had been beaten by prison guards. Photos released last week showed her with a large bruise on her abdomen.
The opposition leader is serving a disputed seven-year prison term in the eastern city of Kharkiv on abuse-of-office charges described by many in Europe as politically motivated.
Interior Minister Hans-Peter Friedrich - in his secondary role as Sports Minister - said he would boycott the Germany vs Netherlands match in Kharkiv on June 13 if he was forbidden from visiting Tymoshenko before-hand.
Now Germany is pushing for the opposition leader's release on health grounds.
Chancellor Angela Merkel's spokesman Steffen Seibert said on Friday the German government would use "all the means at its disposal" to ensure Tymoshenko received "appropriate and thorough" care.
Director of the Charité hospital in Berlin Karl Max Einhäupl repeated his call on Monday for Tymoshenko to travel to Berlin for treatment, following a visit by a team of his doctors last week to check on her condition.
Ukranian doctors would not be able to treat Tymoshenko's slipped disc which has become chronic and requires attention from a team of various specialists, Einhäupl told the ZDF-Morgenmagazin on Monday. The hospital director has invited Ukranian President Viktor Yanukovych to discuss the matter of her release.
"The Berlin doctors believe that (Yulia Tymoshenko's) treatment would best occur in a German hospital," said Merkel on Friday. "That's what the Foreign Office and the Chancellery are working towards."
Ukrainian politicians responded with outrage on Monday to German ‘interference' over Tymoshenko – who was the face of the 2004 Orange Revolution and is the main political rival of President Viktor Yanukovich.
"We would not like to think that the political leaders of Germany are capable of reviving the methods of the Cold War and making sport a hostage of politics," Ukrainian foreign ministry spokesman Oleg Voloshyn told the Interfax-Ukraine news agency.
Director of Bayern Munich club Uli Hoeness added his voice to the fray on Sunday, calling on the German team and UEFA president Michel Platini to add to the mounting political pressure on the Ukrainian authorities.
"I really hope that Michel Platini will clearly express his opinion in the right places," Hoeness told Spiegel on Sunday. As for the German team, "the players are smart enough to form their own opinions," he said.
Pressure is mounting elsewhere as the Czech president joined the German, Slovenian and Austrian presidents in turning down an invitation to a meeting of European presidents to be hosted by Ukraine in May.