Russia struggles to respond to Ukraine's incursion as advancing forces destroy key bridges and war potential

Ukrainian forces say they've blown up a second strategically significant bridge in the Kursk region of Russia as Kyiv continues its incursion, while Moscow has yet to mount a robust response to the ambitious cross-border operation.

As many as 5,000 Ukrainian soldiers are taking part in the incursion into Russian territory that began almost two weeks ago, The Wall Street Journal reports. Kyiv claims it has taken control of 82 settlements in the region over an area of 1,150 square kilometers (444 square miles) since the border raid began.

Ukrainian forces have concentrated a number of their assaults on key transport and fuel infrastructure in Kursk in a bid to make it harder for Russia to resource and resupply its troops fighting in eastern and southern Ukraine.

Last Friday, Ukraine said its forces had destroyed a key bridge over the Seim River in Kursk, with the bridge reportedly used to transport equipment to the front line. Russian officials confirmed the attack took place and said the bridge's destruction would hamper efforts to continue evacuating thousands of citizens in the region.

On Saturday night, Ukrainian forces struck a Russian oil depot in the Rostov region that supplies oil to the Russian military. Ukraine's General Staff commented on the attack that "measures to undermine the military and economic potential of the Russian Federation continue."

Ukraine's air force on Sunday claimed it had destroyed a second bridge in Kursk, which Russia used to supply its troops. Aerial footage posted on social media purported to show the blast creating a large hole in the bridge near the village of Zvannoe. CNBC could not independently verify the footage.

"Minus one more bridge," Ukrainian Air Force commander Lt. Gen. Mykola