BERLIN - German Chancellor Angela Merkel urged Ukrainian leaders on Thursday to give jailed ex-Premier Yulia Tymoshenko "proper treatment" for her ailments, as more top officials announced they would boycott the Euro 2012 soccer championship co-hosted by Ukraine.

Merkel insisted that she had not yet decided whether to stay away from the matches in Ukraine, but said her priority now was the former leader's health.

Euro 2012 is the continent's most prestigious soccer tournament, taking place only once every four years. The dispute over Tymoshenko, Ukraine's top opposition figure, is coming as a big blow to the country's hopes of using the tournament to boost tourism and trade with the 27-nation European Union. Ukraine, which is not in the EU, is co-hosting with EU member Poland.

"Much more important than my travel plans is that we must now do everything possible to see that Yulia Tymoshenko gets the proper treatment," Merkel was quoted as saying by the Koelner Stadt-Anzeiger newspaper. "Our offer stands for her to receive this medical treatment in Germany."

European Union President Herman Van Rompuy, meanwhile, announced Thursday he would not travel to any of the matches in Ukraine, joining other top officials such as European Commission President Jose Manuel Barroso and the governments of Austria and Belgium.

Tymoshenko, 51, is on a hunger strike to protest alleged mistreatment in an Ukraine prison where she is serving a seven-year sentence on charges of abusing her power while in office. She claims guards punched her while forcibly taking her to a hospital to be treated for debilitating back pain.

The West has criticized her sentence as being politically motivated for Tymoshenko is a big rival of Ukrainian President Viktor Yanukovych. His government has denied any claims of bias in the case.

"The Tymoshenko case has dramatically darkened the chances of Ukraine improving its image during the Euro," Ukrainian political analyst Vadym Karasyov said. "Ukraine will be judged not by how well it organizes a European sporting event, but by Tymoshenko's case, the political repressions, the bruises on Tymoshenko's body that she said she got in prison."

In Warsaw, Polish Prime Minister Donald Tusk said while he is disturbed by Ukraine's treatment of Tymoshenko and is urging Ukraine to observe international human rights standards, he will not back a boycott of the June 8-July 1 Euro 2012 tournament.

"I have appealed multiple times to the authorities in Ukraine not to let politics ruin this national celebration and nothing will affect our determination to fight for human rights and alleviate the situation of Yulia Tymoshenko," he told reporters.

Ukraine's Foreign Ministry on Thursday criticized the calls to boycott the soccer championship, saying that would only harm the image of the European sports event.

"Those who seek to make a target out of Euro 2012 help neither to reform the Ukrainian court system nor to strengthen democratic institutions and the rule of law in Ukraine," ministry spokesman Oleksandr Dikusarov said in a statement. "All of these issues lie objectively in a sphere other than the celebration of football (soccer)."

Russian President-elect Vladimir Putin also weighed in, saying Russia would be willing to let Tymoshenko to come there for medical treatment. But Putin agreed that the Tymoshenko situation should not involve Euro 2012.

"One must not in any circumstances mix politics, business and other questions of this sort with sports," he said Thursday.

In Kyiv, Parliament Speaker Volodymyr Lytvyn acknowledged that the Tymoshenko case has put Ukraine in a difficult position. "All of this has become a problem for the country and obviously for Europe," said Lytvyn, a Yanukovych ally.

During a visit to Lithuania, U.S. Sen. John McCain joined the chorus calling for Tymoshenko to receive urgent medical care. McCain also said Ukraine's leadership cannot expect closer relations with Europe while it persecutes political opponents and fails to hold free and fair elections.

"The message needs to be clear and sent now by the EU to the Ukrainian government," he said.