Tymoshenko is serving a seven-year prison sentence on a conviction regarding charges she abused her authority when, as prime minister in 2009, she helped broker a deal with Russian natural gas company Gazprom.
Ukrainian President Viktor Yanukovych reportedly told German Chancellor Angela Merkel he'd let the former prime minister free for $7 billion, half of what the president said was stolen by Tymoshenko, reports Russian news agency RIA Novosti.
Oleh Rybachuk, a former presidential chief of staff from a previous administration, was quoted as saying, he's "repeatedly" heard of the so-called ransom offer from several sources, including a Merkel adviser.
Tymoshenko led the country's Orange Revolution in 2005. She staged a hunger strike early this year to protest her treatment in prison and her supporters say the charges against her are politically motivated.
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