He also chastised current European officials for giving Ukrainians "false promises" over the future of their EU candidacy, saying that being admitted to the bloc would be "neither good for the EU nor for Ukraine."

"Anyone who has had anything to do with Ukraine knows that this is a country that is corrupt at all levels of society. Despite its efforts, it is not ready for accession; it needs massive internal reform processes," he said.

"You shouldn't make false promises to the people in Ukraine who are up to their necks in suffering," he explained. Juncker further emphasized, "I am very angry about some voices in Europe who are telling Ukrainians that they can become members immediately."

The reform process and waves of European law packages countries are expected to adopt before they can hope to enter typically takes years or realistically over a decade.