The European Union on Friday insisted that Ukraine free jailed opposition leader Yulia Tymoshenko if it expects to sign a deal bringing Kiev closer to Europe.
"Requests from the EU on Tymoshenko's case are still on the table," Lithuanian President Dalia Gribauskaite told reporters at a regional forum in Yalta in southern Ukraine.
"Without a solution of this question I do not see a possibility for the signing of the (association) agreement," she added.
The EU, whose rotating presidency is currently held by Lithuania, has pressed Ukraine to release Tymoshenko or at least allow her to seek medical help abroad for back problems which had kept her in hospital for most of her prison term.
In August, Ukrainian President Viktor Yanukovych pledged to fulfil all the conditions put forward by the EU to sign the agreement, but gave no hint of a breakthrough in the dispute with Brussels over the jailing of Tymoshenko.
He reiterated Friday that he has no legal authority to free Tymoshenko as it is up the courts to decide, but added that he had not yet given a "no" answer.
"We are trying, we are looking for how to approach this most difficult issue related to Tymoshenko," he said, arguing there are pending cases against the opposition leader which "have to be answered".
Kiev is hoping to sign the Association Agreement at the EU's Eastern Partnership summit in Vilnius in November, which would be a first formal step on the road to EU membership.
Tymoshenko was sentenced in October 2011 to seven years in jail on charges of overstepping her authority while prime minister by agreeing a gas deal with Russia.
But she insists her imprisonment was ordered by Yanukovych in a bid to eliminate a dangerous opponent from political life ahead of 2015 presidential polls and her detention has soured Kiev's relations with the EU.
The fiery 2004 pro-democracy Orange Revolution co-leader has seen other legal troubles pile up since her conviction, including a separate trial on tax evasion and embezzlement charges while head of Ukraine's main power utility in the 1990s.
She has also been charged with involvement in the 1996 gangland-style shooting of Ukrainian lawmaker Yevgen Shcherban.
Gribauskaite meanwhile denounced pressure on Ukraine not to sign the Association Agreement.
"The pressure is growing. I hope that Ukraine has the strength to resist this pressure,"Grybauskaite said.
Russia President Vladimir Putin in August warned that Moscow could not simply stand by if Ukraine opted for such an important political and trade tie-up with the EU.
"Ukraine is a very large, strong and important country and it must make its own, independent decision about what kind of a country it wants to be and what kind of future it will have," Grybauskaite said.
Signing the Association Agreement would open up EU markets for Ukrainian exports and mark a decisive turn towards the West, stoking concern in Moscow which considers Kiev to be firmly in its sphere of influence.