The United Nations says more than 4.5 million people have fled Ukraine since Russia’s invasion began 46 days ago on February 24. On Saturday, residents of government-controlled parts of eastern Ukraine were urged to evacuate immediately, as Russia began a major offensive in the Donbas region. Satellite images show Russia has amassed an eight-mile convoy of military vehicles inside Russia east of the Ukrainian city of Kharkiv.

Over the weekend, Russian President Vladimir Putin tapped Aleksandr Dvornikov to be Russia’s new battlefield leader in Ukraine. The general most recently oversaw Russian troops in Syria, where he was accused of targeting civilians and medical facilities.

In the Ukrainian city of Kramatorsk, the death toll has risen to 57 following a missile attack on Friday on a crowded train station packed with civilians trying to flee the area. Ukraine and Russia have accused each other of carrying out the strike.