Key powers failed to clinch a breakthrough in talks Wednesday seeking a lasting peace deal in Ukraine, with negotiations stumbling over the thorny issue of local elections in the rebel-held zone.
"The result is, at the very best, mixed," said German Foreign Minister Frank-Walter Steinmeier after hosting the talks with his Russian, Ukrainian and French counterparts.
Even if there had been "clear progress" on the issue of security in war-wracked eastern Ukraine, Steinmeier said the "political process remained difficult and without a breakthrough today".
Germany and France are spearheading efforts to end the fighting between Ukrainian troops and pro-Kremlin rebels -- whom the West believes are backed by Russia -- in Ukraine's eastern industrial heartland.
Although a peace deal was agreed in Belarussian capital Minsk in February 2015, a truce has been frequently violated.
Both sides have also been unable to break a deadlock on organising local elections in the rebel-held Donetsk and Lugansk regions.
In a sign of the hostility over the issue, Ukraine's Foreign Minister Pavlo Klimkin said the Russians had presented a version of electoral legislation for the polls.
But he told his Russian counterpart Sergei Lavrov that "we are capable of writing Ukrainian legislation by ourselves, and we don't need any advice," according to remarks reported by Interfax agency.
Steinmeier on Tuesday expressed exasperation at the pace of the talks, complaining that "in terms of seeking a political solution, things have been moving along at snail's pace".
"It cannot go on like that," he said.
The pro-Moscow rebellion has now killed more than 9,300 people and, along with Russia's annexation of Ukraine's strategic peninsula of Crimea, it has plunged Russia's relations with the West to a post-Cold War low.