"It should be clear to both sides that there can be no military solution to the conflict," Steinmeier told the daily Hannoversche Allgemeine Zeitung, adding that both Russia and Ukraine had to be serious about a permanent truce.

Following a meeting between him and his Russian, Ukrainian and French counterparts on Monday that ended without agreement, Steinmeier does not believe that quick progress can be made, given that there are plenty of unresolved issues.

"The problem is that we're talking about where to draw the ceasefire line, the withdrawal of heavy weaponry and fighters from abroad as well as the exchange of prisoners - all while the winter weather is exacerbating the situation in eastern Ukraine on a daily basis," he said in an interview published on Thursday.

"It's an incredibly complicated situation," he added. A truce agreed upon last September in the Ukrainian city of Minsk has been violated frequently.

Meanwhile, the EU's foreign policy chief, Federica Mogherini, told lawmakers on Thursday that the EU must discuss how "we could think of restoring, partially, options and instruments for cooperation on [the] rule of law and the judiciary with Russia."

Relations with Russia will be at the heart of next Monday's meeting of EU foreign ministers. The bloc is divided on how to deal with Russia, with many eastern European countries fearing that the EU might be too soft on Moscow. Italy and France, meanwhile, are among the countries plumping for a more conciliatory stance.

ng/sb (AP, Reuters, AFP)