"Vladimir Putin drew attention to the worsening humanitarian situation and an increase in the number of Ukrainian refugees in Russia," the Kremlin said in a statement following the talks.
The leaders discussed "the need to extend the truce" and the observance of the ceasefire by the warring sides in Ukraine, the Kremlin said, adding the call took place at the initiative of the German side.
A one-week ceasefire announced by Ukrainian President Petro Poroshenko last week is set to expire tomorrow after inconclusive talks.