KIEV, Sept. 13 - Jailed opposition leader Yulia Tymoshenko on Thursday said she several times detected unusually high levels of radiation in her hospital quarters, accusing President Viktor Yanukovych of using Stalinist methods against her.

Tymoshenko issued a statement after prison authorities had searched the quarters and confiscated two radiation measuring devices hidden in a secret place.

"Only he is capable now of taking special measures against my health and my life," Tymoshenko said, Reuters reported.

Tymoshenko made her allegations in a statement on her party's website after prison officials carried out a search of her hospital room in the city of Kharkiv, where she is confined with back trouble, and took away some of her possessions.

"Today a search worthy of the best traditions of 1937 was carried out in my ward," Tymoshenko said, referring to the purges of Soviet dictator Josef Stalin.

The 51-year-old politician is serving a seven-year sentence in Kharkiv on an abuse-of-office charge linked to a gas deal she brokered with Russia in 2009 when she was prime minister.

Prolonged hospital treatment has prevented a second trial for alleged embezzlement and tax evasion going ahead.

She denies all charges against her and says she is the victim of political revenge by Yanukovych who narrowly beat her for the presidency in February 2010.

Tymoshenko said the devices had been given to her to measure radiation levels and on four occasions they had shown that acceptable levels were exceeded. She did not say who had given her the devices.

"I had planned to pass these devices soon to my defense counsel for this information to be made public," she said.

"I am convinced this search was organized on the direct orders of Yanukovych aimed at confiscating the devices."

Ukraine's prison service confirmed officials had searched her hospital quarters on Thursday and confiscated "technical devices" and medicine of unknown origin which they found hidden.

"These objects and medicine have been handed over for examination," the prison service said in a statement.

A Ukrainian high court last month rejected her appeal against the abuse-of-office conviction and Tymoshenko's lawyers now plan to challenge it in the European Court for Human Rights.

Tymoshenko would have been a major political adversary of Yanukovych in an October 28 parliamentary election in which his Party of the Regions is fighting to hold on to its majority.

The European Union has supported Tymoshenko, calling her case an example of selective justice and shelving agreements on free trade and political association with Ukraine over the issue.

Tymoshenko led the 2004 Orange Revolution protests that doomed Yanukovych's first bid for the presidency, and she went on to serve twice as prime minister. Yanukovych has refused to intervene in Tymoshenko's case despite being urged to do so by the West. (rt/ez)