NEW YORK, April 15 - German Finance Minister Wolfgang Schaeuble said on Wednesday that the United States must play an important role in helping to solve the crisis in Ukraine while European resolve to come to a non-military solution remains strong, Reuters reported.

"We will not fall back into the history of a 100 years ago that you can change with military force. For this we need the United States," Schaeuble said in answer to a question following a presentation at the Council on Foreign Relations in New York.

"We know that we need the United States. We know that we have to care as Europeans on this matter, better than most have expected that the Europeans would do, but it is difficult to get it. A difficult job," he said.

NATO's top commander, U.S. General Philip Breedlove, voiced concern on Wednesday at a new flare-up of fighting in Ukraine and urged Russia to stop fuelling the conflict.

"Concerned by renewed fighting in Ukraine. Vital all sides pull back verifiably, Russia stops fuelling conflict," NATO's Supreme Allied Commander, Europe, said on Twitter.

Six servicemen were killed and 12 wounded in eastern Ukraine in the previous 24 hours despite a ceasefire deal, Ukraine's military said on Tuesday. Russia denies NATO's assertions that it has sent troops and equipment to Ukraine.

More than 6,000 people have been killed in Ukraine since fighting started last April when pro-Russian rebels opposed to a new pro-Western government declared independence from Kiev.

Ukraine and Russia signed a cease-fire agreement in Minsk in February, reducing the incidence of violence between the two sides, but not eliminating it completely.

Group of Seven foreign ministers said on Wednesday that Western sanctions against Russia can only be lifted once Moscow fulfills the Minsk agreement and respects Ukraine's sovereignty. (rt/ez)