Ukraine and the European Union scheduled the signing of an association agreement during a Nov. 29 summit in Vilnius, Lithuania. Ukrainian legislators were expected to vote on a final series of measures that would clear the way for association but said Thursday the effort was suspended.
A representative from the European Commission told the National News Agency in Ukraine it was reviewing the development.
"We are studying the situation and preparing our response," the representative said on condition of anonymity.
Ukrainian leaders Thursday rejected a measure that would've allowed jailed former Prime Minister Yulia Tymoshenko get medical treatment in Germany. She was convicted on corruption charges in 2011, a ruling she and her supporters said was politically motivated.
Russia's state news agency RIA Novosti reported Thursday lawmakers in Kiev said the decision to suspend association efforts was motivated by the need to ensure Ukraine has strong economic ties to Russia.
The Russian report said Russian President Vladimir Putin said he'd consider a trilateral deal with the EU and Kiev provided Kiev backs away from its association ambitions.