Moscow says that Ukraine has struck and damaged a third bridge in the Kursk region, as Kyiv forces attempt to expand its incursion within Russian territory.

Russia’s Investigative Committee on Monday confirmed the attack on the bridge located along the River Seym, which winds through Kursk.

Ukrainian authorities have yet to comment on the Russian claim.

In another sign of escalation on Monday, Russia said its marines have captured a group of 19 Ukrainian soldiers in the region, the state RIA news agency reported. The outlet described the Ukrainians as “saboteurs.” RIA published what it said was video of the captured troops.

On Sunday, Ukraine said that it has destroyed a second bridge across River Seym.

The attacks on the region’s bridges in a matter of days come as Ukraine presses a cross-border offensive that began on August 6.

On Friday, it said it had struck a bridge in the Russian town of Glushkovo.

“Minus one more bridge,” Ukrainian Air Force Commander Mykola Oleshchuk wrote on Telegram on Sunday, publishing an aerial video of a blast tearing through the bridge.

He said the attacks were designed to disrupt Russian supply lines.

“The Air Force aviation continues to deprive the enemy of logistical capabilities with precision air strikes,” Oleshchuk said, without giving a date for the attack.

Hours later, Ukrainian President Volodymyr Zelenskyy praised the incursion and stated its aims for the first time.

“It is now our primary task in defensive operations overall: to destroy as much Russian war potential as possible and conduct maximum counteroffensive actions. This includes creating a buffer zone on the aggressor’s territory,” he said in his evening address.

According to Russia’s Mash news site, the attacks left only one bridge in the area intact, potentially complicating Moscow’s attempts to replenish its forces and evacuate civilians.

Until now, Kyiv said little about the goals of the cross-border assault.

The incursion began with tanks and other armoured vehicles, the largest attack on Russia since World War II.

Ukraine’s military chief, Oleksandr Syrskii, claimed last week that his forces had advanced across 1,000sq km (390sq miles) of Kursk, although it was not possible to independently verify the extent of its control.

On Sunday, Moscow claimed to have taken the village of Svyrydonivka, about 15km (nine miles) from Pokrovsk, which is a key logistics hub for Ukrainian troops and towns across the eastern front.