"The chief aim now is to prevent a further deterioration of the military conflict and a renewed political escalation between Kiev and Moscow. This is worth every effort," German Foreign Minister Frank-Walter Steinmeier said in a statement.
He said he had called the meeting at the request of his Russian and Ukrainian counterparts Sergei Lavrov and Pavlo Klimkin, and that Laurent Fabius of France would also take part.
The group last met in Berlin on January 12 when they ended their talks without being able to set a date for a hoped-for peace summit on ending the conflict.
"We have spoken intensively with each other in recent days in order to look for political compromises in the ever more difficult situation," he said.
Russian-backed insurgents today assaulted the remnants of a Ukrainian force hanging onto a ruined airport near the rebels' main stronghold of Donetsk.
The past week's escalation in fighting and effective shredding of a repeatedly violated September truce has been accompanied by claims from Kiev's pro-Western government that 700 new Russian soldiers have been deployed across the border into Ukraine's separatist east.