PRAGUE (Reuters) - Czech President Vaclav Klaus has cancelled a visit to Ukraine next month over the imprisonment of Ukraine's former prime minister Yulia Tymoshenko, a spokesman said on Monday.
Klaus has joined German President Joachim Gauck who has decided to cancel participation at a summit of central European presidents in the Black Sea resort of Yalta on May 11-12.
"There are several reasons (for Klaus's absence) but this is the main one," the president's spokesman Radim Ochvat said.
The Czech Republic has been critical of the treatment of Tymoshenko, the main political rival of President Viktor Yanukovich, who is serving a seven-year jail term after her conviction on abuse-of-office charges seen by the European Union as politically motivated.
Tymoshenko has been suffering from back pain. Germany has offered to arrange for her treatment but it is not clear if the government would let her go and her family says she will not leave Ukraine.
Tymoshenko, 51, has been on hunger strike since last Friday when she said she was assaulted by guards. Prison authorities have said she may be force-fed.
The Czech Republic has granted political asylum to Tymoshenko's husband Oleksander.
Ukraine faces more potential boycotts by European politicians during the Euro 2012 soccer tournament it will co-host with Poland in June. Germany's Der Spiegel magazine reported on Sunday that Chancellor Angela Merkel may shun the tournament if Tymoshenko remains in jail.
(Reporting by Jan Lopatka; Editing by Janet Lawrence)