Ukrainian forces stop Russian advance towards Sloviansk - presidential aide

Ukrainian troops have held up an advance by Russian forces from the northeastern city of Izyum towards nearby Sloviansk, Oleksiy Arestovych, a Ukrainian presidential advisor said on Wednesday.

"They have focused their forces there, that is where they are trying to advance, but so far they are not succeeding," he said in a video address.

Arestovych also said that Ukrainian forces in the besieged city of Mariupol have been holding out, despite persistent Russian attacks on the Azovstal steel plant.