A Ukrainian court started hearing the appeal of jailed former prime minister Yuila Tymoshenko on Wednesday.
The 51-year-old did not appear for the hearing in Kiev. Her lawyers said she is extremely ill.
Tymoshenko was sentenced to seven years in October for ignoring a cabinet vote and ordering state-run Naftogaz to sign a gas import deal with Russia in 2009.
Diplomats in Brussels say the case has damaged Ukraine’s chance of closer ties with the EU amid concerns her trial was unfair.
Sergiy Vlasenko, one of her lawyers, said the judge hearing the appeal would be unable to be objective because “she had not even read all the documents relating to the case.”
He added Tymoshenko’s health problems merit an immediate release and that a new, complete investigation should be opened.
Tymoshenko’s legal team argue the case is politically motivated, a mere ruse by President Viktor Vanukovych to sideline his bitter rival.
Our correspondent Sergio Cantone said the appeal will pose a challenge to the Ukrainian head of state.
He points out that Tymoshenko has argued that during his tenure Ukraine has become a country that no longer respects the rule of law.