Seventy-five years after the Nazi invasion of the Soviet Union, which led to the deaths of tens of millions, Germany's foreign minister is warning "Europe is at risk of splitting along new divides."

In an op-ed printed Wednesday in Russia, Ukraine and Belarus, Frank-Walter Steinmeier cautions "peace in Europe cannot be taken for granted, not even today."

Referring to Russia's annexation of Crimea, Steinmeier says "unilateral shifting of borders in breach of international law and the failure to respect the territorial integrity of neighboring countries... take us back to the times from which we believed we had escaped, times that nobody can wish for."

Steinmeier urged all sides to return to dialogue, saying "the leaders of today have the duty to draw the right lessons from our common past."