Radek Sikorski said Monday that Ukraine's justice system still needs improvements, especially the electoral law and regulations concerning prosecution.
The EU believes that jailed former Prime Minister Yulia Tymoshenko has not been given a fair trial and insists the matter be resolved before the deal can be signed.
The signing of the agreement is scheduled for the fall in Vilnius.
It would be a major step in Ukraine's bid to join the European Union.
Poland supports Ukraine's European aspirations.
Sikorski said, "There will be no signing if Ukraine does not do what it should do."
Source: Edmonton Journal