The European Union shares part of the blame for the Ukraine crisis by initially creating the impression Kiev had to choose between Russia and the EU, Germany's vice chancellor says.

Sigmar Gabriel, who is also economy and energy minister, stressed that this did not justify Russian President Vladimir Putin's intervention in the former Soviet satellite country.

"Sure, the EU also made mistakes, but that doesn't justify Russia's behaviour," Gabriel told the Rheinische Post daily, referring to Brussels' offer of an association pact to Kiev last year.

"It certainly was not wise to create the impression in Ukraine that they must choose between Russia and the EU. But again - that wasn't and isn't a justification to plunge a country into chaos."

Germany's former chancellor Gerhard Schroeder, a Social Democrat like Gabriel and a confidant of Putin, has sparked controversy by saying the "fundamental error" lay with the EU, which had "ignored that Ukraine is a culturally deeply divided country".

Gabriel, in comments published on Wednesday, said "the key lies with Russia, with President Putin" to resolve the standoff.

"He must use his influence with the (pro-) Russian separatists and ensure that there are no further escalations of emotion and nationalism. Putin must face up to his responsibility."

As German Foreign Minister Frank-Walter Steinmeier continues his months of diplomatic efforts to mediate in the crisis, Gabriel stressed Berlin's view that "we must avoid any form of military conflict".

"The recurring demand to include Ukraine into NATO really is absurd," he added.

Had this happened already, Gabriel said, "we would now be in the middle of a confrontation".