Ukrainian troops have withdrawn from the embattled eastern town of Siversk, as Russia continues its steady - albeit slow - advance, BBC reported. 

The Ukrainian military said on Tuesday it acted "to preserve the lives of our soldiers and the combat capability of units", adding that Russian forces had a "significant advantage in manpower".

The capture of Siversk brings Russia closer to the last remaining "fortress belt" cities of Sloviansk and Kramatorsk still in Ukrainian hands in the industrial Donetsk region, according to BBC.