Russia's Defense Ministry said Saturday it had resumed "offensive actions" in Ukraine after announcing a ceasefire earlier in the day to allow residents of two besieged cities to evacuate.

"Due to the unwillingness of the Ukrainian side to influence nationalists or extend the regime of silence, offensive actions have been resumed at 18:00 Moscow

Russian Foreign Minister Sergei Lavrov said Saturday that Moscow is demanding guarantees from the U.S. before backing the Iran nuclear deal, citing the current wave of Western sanctions against Russia.

Lavrov said that the nuclear talks have covered most issues and "from our point of view, if Iran agrees, this document can already be launched into

Russia's flagship airline Aeroflot said Saturday that it was suspending all its international flights beginning March 8, as Moscow faces waves of Western sanctions over its military incursion in Ukraine.

An Aeroflot statement on the "temporary suspension of all international flights from March 8," cited new "circumstances that impede the operation

The Ukrainian port city of Mariupol delayed a planned evacuation of residents Saturday, blaming Russian forces for breaking their temporary ceasefire to allow civilians to flee one of the war's fiercest battles.      

Russia has besieged the strategic city, which proudly resisted Moscow-backed rebels during a 2014 conflict, cutting off electricity,