Pressure on Russian forces mounts after Ukraine's advances

The new line comes after a Ukrainian counteroffensive punched a hole through the previous front line in the war and recaptured large swaths of land that borders Russia

Western defence officials and analysts on Saturday said they believed the Russian forces were setting up a new defensive line in Ukraine's northeast after Kyiv's troops broke through the previous one and tried to press their advances further into the east.

The British Defence Ministry said in a daily intelligence briefing that the line likely is between the Oskil River and Svatove, some 150 kilometres southeast of Kharkiv, Ukraine's second-largest city.

The new line comes after a Ukrainian counteroffensive punched a hole through the previous front line in the war and recaptured large swaths of land in the northeastern Kharkiv region that borders Russia.

Moscow “likely sees maintaining control of this zone as important because it is transited by one of the few main resupply routes Russia still controls from the Belgorod region of Russia”, the British military said, adding that ”a stubborn defence of this area" was likely, but that it remained unclear whether the Russians would be able to withstand another concerted Ukrainian assault.

Ukrainian forces, in the meantime, continue to cross the key Oskil River in the Kharkiv region as they try to press on in a counteroffensive targeting Russian-occupied territory, according to the Washington-based Institute for the Study of War.

The Institute said in its Saturday report that satellite imagery it examined suggest that Ukrainian forces have crossed over to the east bank of the Oskil in Kupiansk, placing artillery there.

The river, which flows south from Russia into Ukraine, had been a natural break in the newly emerged front lines since Ukraine launched its push about a week ago.