Russia continues to engage in combat with Ukrainian forces for the third consecutive day following a significant invasion.

MOSCOW—Russian forces were engaged in a third day of battle with Ukrainian troops on Thursday after breaching the Russian border in the Kursk region, posing a threat to the world’s largest nuclear power plant and prompting Moscow to call in reserves.

In a significant Ukrainian offensive on Russia during the two-year conflict, approximately 1,000 Ukrainian troops breached the Russian border on August 6 with tanks and armored vehicles, supported by drones and heavy artillery, according to Russian authorities.

The Ukrainian forces pushed through the fields and forests towards the north of the border town of Sudzha, the final operational trans-shipment point for Russian natural gas to Europe via Ukraine.

President Vladimir Putin condemned the attack as a “major provocation,” while the White House, as Ukraine’s main supporter, claimed to have had no prior knowledge of the attack and expressed a desire to gather more information from Kyiv.

Russia’s top general, Valery Gerasimov, informed Putin on Wednesday that the Ukrainian offensive had been stopped in the border region.

The Russian defense ministry reported on Thursday that the army and Federal Security Service (FSB) had halted the Ukrainian advance and were engaging Ukrainian units in the Kursk region.

“Units of the Northern group of forces, in conjunction with the FSB of Russia, are actively eliminating armed groups from the Armed Forces of Ukraine in the Sudzhensky and Korenevsky districts of the Kursk region, adjacent to the Russian-Ukrainian border,” the ministry stated.

The ministry reported that Ukraine suffered losses of 82 armored vehicles, including eight tanks, during the attack.

The Ukrainian military has not commented on the offensive in Kursk.

Some Russian bloggers criticized the lack of border defense in the Kursk region, claiming that Ukrainian forces easily breached the defenses.

“The enemy penetrated our defense lines quite effortlessly,” said popular Ukrainian-born pro-Russian military blogger Yuri Podolyaka, noting the absence of complete defensive preparations in the Kursk region despite the ongoing conflict.

The battles in Sudzha are occurring at a critical moment in the conflict, which is the most significant land war in Europe since World War Two.

Ukraine aims to restrain Russian forces, who currently control 18 percent of its territory, though the strategic implications of the border offensive remain unclear.

Russian media reported the evacuation of several thousand individuals from the Kursk region.

Former Russian president Dmitry Medvedev viewed the Ukrainian attack as an effort to divert Russia’s resources from the front and demonstrate Ukraine’s resilience to the West.

As a response to the Kursk attack, Medvedev suggested expanding Russia’s war objectives to encompass the entire Ukraine territory.

“From now on, the SVO (Special Military Operation) should have an overtly extraterritorial aspect,” Medvedev remarked, advocating for Russian forces to advance to Odesa, Kharkiv, Dnipro, Mykolayiv, Kyiv, and beyond.

“Our operations will cease only when deemed advantageous and beneficial to us,” he added.

Gas flow through Sudzha continues, with enhanced security measures around the Kursk nuclear power plant, located approximately 60 km northeast of the town, according to Russia’s National Guard.