The trial of jailed Ukrainian opposition leader Yulia Tymoshenko has been delayed again until late June.
State prosecutors asked the supreme court to delay her appeal, due to begin on Tuesday, because they needed more time to prepare and due to her absence.
Ms Tymoshenko was moved from prison into a hospital to be treated for chronic back pain last week.
The country's prime minister said Ms Tymoshenko had been convicted by a free and independent judiciary.
Prime Minister Mykola Azarov said his predecessor invited observers from European Union nations to Ukraine to watch the appeal process.
"They can review the documents. They can learn more about the procedure and they can listen to the arguments," he said in Brussels.
The court set a new date of 26 June for the hearing, which falls near the end of the European football championships Ukraine is co-hosting.
Ukraine has been threatened with a political boycott of the championship over its treatment of the former prime minister.
Her lawyers have said that her appeal was delayed on political grounds.
Last week, Ms Tymoshenko ended a 20-day hunger strike after being moved to a hospital in Kharkiv where she is being treated by a German doctor.
The EU has chided Kiev over her plight.
Last week, Lithuania's president visited her and said she found her to be in a good mood, but warned that "Europe's trust in Ukraine is dwindling".
Ms Tymoshenko played a key role in the pro-Western Orange Revolution in 2004 and says her imprisonment is an act of political revenge by Ukraine's President Viktor Yanukovych.
The authorities have rejected Ms Tymoshenko's allegations. She was jailed for seven years in October, for abuse of power during her time as prime minister.