Ukraine has rejected an offer by Russia for Yulia Tymoshenko, the jailed former prime minister, to receive medical treatment in Moscow.
Russian President-elect Vladimir Putin had on Thursday offered to host the opposition leader in Russia for treatment after claims of abuse in detention.
"It was president elect Vladimir Putin who made this offer to the Ukrainian authorities on Thursday saying it would be our pleasure for Yulia Tymoshenko to come to Russia for medical treatment," Al Jazeera's Sue Turton reported from Moscow on Friday.
"But it was swiftly followed by a rebuttal from the Ukrainian prosecution office saying they would not allow this to happen - for a prisoner to leave the country for medical treatment under Ukrainian law."
Tymoshenko, 51, has been on a hunger strike since April 20 to protest her alleged beating by wardens in a prison where she is serving a controversial seven-year term for abuse of office - charges some say were politically motivated.
Putin made the offer in a bid to defuse the crisis that is putting pressure on the Ukraine ahead of it co-hosting next month's Euro 2012 football tournament with Poland.
But Putin has also rallied to his neighbour's defence by saying he disagreed with EU states' attempts to mix politics with sport.
Turton said the reaction to Putin was the same response the Ukrainian authorities gave to Germany after it also offered Tymoshenko medical attention there.
German Chancellor Angela Merkel urged Ukrainian leaders on Thursday to give Tymoshenko "proper treatment" for her ailments.
'Politicising' sporting events
Germany, along with other countries including the UK and the Netherlands are considering a boycott of Euro 2012.
Politicians from Austria and Belgium have already said they would not attend, in protest of Tymoshenko's treatment by Kiev authorities.
European Commission chief Jose Manuel Barroso has also made a decision to skip the games,
"Ukraine is reacting quite angrily to some of the European politicians saying they won't be turning up," Turton said.
"They say the threat of a boycott was destructive, they said that it was undermining the whole image of the Euro 2012 championships and it was detrimental to both Poles and Ukrainians."
In a statement released by its foreign ministry on Thursday, Ukraine said: "We view as destructive attempts to politicise sporting events, which since ancient times have played a paramount role in improving understanding and agreement between nations.
"An attack on this big dream undermines the chances of... all the former Socialist Bloc members to prove that their economic, human and scientific potential can turn them from the debtors of Europe to its engine of growth."
Poland has criticised Tymoshenko's imprisonment, with Donald Tusk, the prime minister, saying Ukraine's reputation will "suffer dramatically" if no humanitarian solution is found.
Tymoshenko's supporters meanwhile posted pictures of bruises on her stomach, saying they confirmed her claims of torture, images that were then reproduced by the media.
"This is a PR disaster that doesn't seem to want to go away," our correspondent said. "It's not just the sports field but the political arena that the treatment of Yulia Tymoshenko is having an impact on".
There have been reports that the presidents of Austria, the Czech Republic, Germany, Italy and Slovenia have rejected an invitation to the Ukrainian Summit of Central and Eastern leaders to be held in Yalta next week.