MOSCOW — Germany’s foreign minister, Frank-Walter Steinmeier, urged Moscow on Monday to reduce tensions with Ukraine after what Russian officials said was a border skirmish with Ukrainian forces in which two Russian soldiers died.

Germany is Russia’s closest ally in trade and politics among the major European powers, and Mr. Steinmeier has used this position to exert diplomatic pressure. He met Monday with his Russian counterpart, Sergey V. Lavrov, in the Ural Mountains city of Yekaterinburg.

Mr. Steinmeier said both Russia and Ukraine should step back from a looming confrontation along their de facto border on the Crimean peninsula, where Russia said two of its soldiers died in a skirmish with a Ukrainian commando group that had slipped across. Russia annexed Crimea in March 2014.