Russia's preparing new offensive in eastern Ukraine?

Russia's preparations for a new offensive in eastern Ukraine appear to have intensified. Officials in the eastern Ukrainian region of Luhansk say Russian tanks have started advancing for a renewed assault. Meanwhile the US and UK governments both say they are investigating reports that chemical weapons have been used by Russia in the besieged southern port of Mariupol In his nightly address, Ukraine's president Volodymyr Zelensky urged the West to do all it could to deter the Kremlin from using such weapons. Justin Webb heard the latest from the governor of Donetsk region Pavlo Kyrylenko and the UK armed forces minister James Heappey. (Image: pro-Russian troops in Mariupol, Image: Reuters)