KHARKIV, Ukraine - Ukraine on Tuesday was reduced to calling off a Central Europe regional summit after most heads of state boycotted it over the treatment of jailed former Prime Minister Yulia Tymoshenko.

The embarrassing move came after a dozen heads of state, including the German and Czech presidents, had refused to attend the Central and Eastern European summit to be held Friday and Saturday in the Crimean resort city of Yalta after Tymoshenko went on a hunger strike to protest an alleged beating by prison officials.

The Ukrainian Foreign Ministry said it decided to postpone the summit until a later date because of the leaders' inability to come.

Ukraine faces harsh Western pressure for the jailing and alleged mistreatment of Tymoshenko, with some politicians calling for boycotting the Euro 2012 football championship the country is co-hosting in June.

The campaign to free and end the mistreatment of Tymoshenko has become a top human rights issue for the European Union and has drawn comparisons with Western sanctions against Belarus, another former Soviet nation on the EU border. Its authoritarian president, Alexander Lukashenko, has cracked down on dissent and sent opposition leaders to jail.

Tymoshenko was sentenced to seven years in prison on charges of abuse of office while negotiating a natural gas import contract with Russian in 2009. Tymoshenko charges that her arch-foe, President Viktor Yanukovych, has ordered her imprisonment to bar her from October parliamentary elections.

Meanwhile, a respected German doctor visited Tymoshenko on Tuesday in her prison in the eastern Ukrainian city of Kharkiv. Dr. Lutz Harms, a neurologist with Berlin's Charite clinic, said that Tymoshenko would be transferred to a local hospital on Wednesday where he would supervise treatment of her back condition.

Dr. Harms said that Tymoshenko was suffering from chronic pain syndrome and would require long and complicated treatment.

Her family and lawyers say Tymoshenko's health has severely suffered after some two weeks of refusing food.