MOSCOW — Separatist forces deployed more arms and manpower Wednesday to an emerging flashpoint in eastern Ukraine, undermining hopes for a new peace initiative taking shape.

Responding to the developments, Ukrainian President Petro Poroshenko cut short a visit to the economic summit in Davos, Switzerland, where he courted European support in the worsening crisis.

The events unfolded ahead of a meeting in Berlin of the foreign ministers of Ukraine, Russia, France and Germany aimed at laying the groundwork for a long-lasting settlement.

In advance of the talks, Russian Foreign Minister Sergey Lavrov proposed both sides in the conflict pull their heavy weapons back from a previously agreed-upon dividing line to help defuse hostilities. Lavrov’s remarks were greeted with cautious approval by his Ukrainian counterpart, Pavlo Klimkin. “Russia needs to confirm (peace deals) through deed not word,” Klimkin said on his Twitter account.