By Rachel Huggins - 08/22/14 08:55 PM EDT
President Obama and German Chancellor Angela Merkel warned that Russia is triggering a "dangerous escalation" of conflict, which has continued to deteriorate since the downing of a Malaysian airliner in Ukraine last month.
They expressed concern that Russian troops on the Ukrainian border, the buildup of Russian military personnel in Ukraine, and Russian shelling into Ukraine heightened unrest in the war-torn region.
Russia claims the decision to move a convoy of more than 200 trucks into Ukraine on Friday was for humanitarian purposes, but Ukraine and the U.S. say Russian failed to abide by conditions set by Ukraine and the International Red Cross, the Associated Press reported.
The call comes a day before Merkel travels to Kiev on Saturday to meet with Ukrainian President Petro Poroshenko, her first trip to the region since the crisis erupted.
Obama is in Martha's Vineyard on the last leg of his two-week vacation; he is scheduled to arrive back in Washington on Sunday.