Ukrainian ex-prime minister Yulia Tymoshenko.

Kiev/Brussels - Ukrainian President Viktor Yanukovich, under fire from European politicians over the treatment of his jailed opponent Yulia Tymoshenko, has ordered prosecutors to investigate her alleged beating by prison guards last week, he said on Thursday. Tymoshenko's jailing on abuse-of-office charges last year has soured Ukraine's ties with the European Union and risks becoming a major embarrassment for the former Soviet republic when it hosts the European football championship in June.

The EU has condemned Tymoshenko's conviction as an example of selective justice and warned Ukraine that its members would not ratify key agreements on political association and free trade as long as she remains in prison.

Triggering a fresh barrage of alarmed statements from European officials, Tymoshenko this week accused prison guards of beating her during a forced move to a hospital last Friday and said she was on a hunger strike.

Prison authorities have denied her allegations, but Ukraine's top human rights official said on Wednesday Tymoshenko was indeed bruised and urged a criminal probe.

“In line with my powers, I have ordered the prosecutor general's office to investigate this issue and I hope we will soon have a concrete answer,” Yanukovich told reporters on Thursday.

Catherine Ashton, the EU foreign policy chief, asked Kiev on Thursday to allow its ambassador to see Tymoshenko in prison and German President Joachim Gauck late has cancelled a planned visit to Ukraine next month citing concerns over her treatment.

Casting a shadow over Ukraine's plans to improve its image by hosting one of the biggest sports events on the continent, the European football championship, this year, EU justice chief Viviane Reding drew UEFA's attention to Tymoshenko's case.

“I would like to take this opportunity to share my personal concerns about the human rights situation in Ukraine, a country where UEFA Euro-2012 matches will be organised, and especially the dramatic situation of Yulia Tymoshenko,” Reding said in an open letter to UEFA head Michel Platini.

“Selective, partial justice should be not be accepted and I hope you will use this great moment that is the UEFA Euro-2012 to relay the values to which we are both attached.”

Tymoshenko is held in a prison in the city of Kharkiv, one of the four Ukrainian Euro venues.

Tymoshenko, 51, was found guilty last October of abusing her powers as prime minister in forcing through a 2009 gas deal with Russia and could be sentenced to up to 12 years in prison in a new tax evasion trial that opened this month.

She has dismissed all charges as part of a Yanukovich campaign against the opposition.

Tymoshenko's lawyers and family say she can barely walk due to chronic back pain but she refuses treatment by state-appointed doctors saying she does not trust them.

The German government has offered to treat Tymoshenko in a German hospital - a move which could remove her from Ukraine for the time of the Euro championship in a relief for Yanukovich - but it is not clear if Kiev or Tymoshenko would agree.

Tymoshenko was one of the leaders of the 2004 Orange Revolution protests which derailed Yanukovich's first bid for presidency and distanced Ukraine from its former Soviet overlord Russia.

She has since served twice as prime minister but lost the 2010 presidential election to Yanukovich after which she and a number of her allies in opposition faced charges of corruption and other crimes. - Reuters