German Foreign Minister Guido Westerwelle met Friday in Kiev with members of the opposition movement, including Eugenia Tymoshenko, daughter of jailed former Prime Minister Yulia Tymoshenko.
Ukraine is working to establish a closer relationship with the European Union. The EU said this year it was "technically ready" to sign an association agreement with Ukraine provided the government "creates the necessary political circumstances."
Conditions range from addressing concerns from last year's parliamentary elections to tackling issues of selective justice. The former prime minister was sentenced in 2011 to seven years in prison on charges she abused her position of authority in brokering a gas deal with Russian energy company Gazprom in 2009.
European leaders said they suspected the charges against Tymoshenko, leader of the country's Orange Revolution in 2005, were politically motivated.
Westerwelle said the Tymoshenko case was of "particular significance" to members of the EU.
"I would like to underline once again just how important it is to us that any indication of selective justice must be avoided in a community of shared values," he said in a statement Friday.
The European Court of Human Rights said in April that some of Tymoshenko's rights were violated in prison.