KYIV (REUTERS) - Russia's war in Ukraine is about to enter a new phase, with most fighting shifting to a nearly 350km front stretching south-west from near Zaporizhzhia to Kherson, parallel to the Dnieper River.

British military intelligence said on Saturday (Aug 6) Russian forces are almost certainly amassing in the south of Ukraine, anticipating a counteroffensive or in preparation for a possible assault.

Long convoys of Russian military trucks, tanks, towed artillery and other weapons continue to move away from Ukraine's Donbas region and are headed south-west.

Battalion tactical groups, which comprise between 800 and 1,000 troops, have been deployed to Crimea and would almost certainly be used to support Russian troops in the Kherson region.

Ukraine's forces are focusing their targeting on bridges, ammunition depots and rail links with growing frequency in its southern regions, including the strategically important railroad spur that links Kherson to Russian-occupied Crimea.