Ukraine has postponed a planned summit of Central and Eastern European leaders, after some of them pulled out to protest the treatment of jailed former Ukrainian Prime Minister Yulia Tymoshenko.

Ukraine's Foreign Ministry said Tuesday the summit will be held at a later date due to the inability of some European heads of state to take part.

The summit was scheduled to take place in Yalta on Friday and Saturday.

About 10 European Union leaders said they will not attend, including German President Joachim Gauck and Czech President Vaclav Klaus.

Germany has been leading Europe's critical stance on the case of Ms. Tymoshenko, who has been on a hunger strike for about two weeks after she said she was beaten by guards.

Ms. Tymoshenko needs medical treatment for a back condition diagnosed by German doctors who say it cannot be treated in Ukraine. Ukraine has refused to allow her to go to Germany for treatment, but has agreed to let a German doctor treat her at a Ukrainian hospital.

On Monday, Ms. Tymoshenko's daughter, Yevgenia, was in Germany in a bid to increase pressure on the Ukrainian leadership to release her mother for medical treatment.

Ukraine could also face a boycott of the upcoming Euro 2012 football games being played there. Ukraine and Poland are co-hosting the football championship games, from June 8 to July 1.

Yulia Tymoshenko was sentenced to seven years in prison last year on charges of abuse of office in a 2009 gas deal with Russia. She is now standing trial on tax evasion charges that could extend her prison time to 12 years. Ms. Tymoshenko denies the charges and says they are part of a campaign by President Viktor Yanukovich to remove his strongest political rival.

Western nations call the charges politically motivated.