Ukrainian troops have captured more than two dozen settlements in Russia's western Kursk region since launching its incursion nearly a week ago, as thousands of residents have been ordered to evacuate, Russian officials said.
Alexey Smirnov, the acting governor of Kursk, said Monday the situation in the region remains "difficult."
"As of today, the enemy controls 28 settlements, the penetration depth into Kursk Oblast is 12 kilometers, the width is 40 kilometers," Smirnov said during an operational meeting with Russian President Vladimir Putin.
The commander-in-chief of the Ukrainian armed forces, Col. Gen. Oleksandr Syrskyi, said Monday that Ukraine controls about 386 square miles of Russian territory as it continues its offensive operation in the Kursk Oblast.
Some 180,000 residents of Kursk have been ordered to evacuate and about 121,000 of them have left their homes in the areas near the border with Ukraine, Smirnov said.
At least 12 people have been killed and 121 others have been wounded in the Kursk region since the Ukrainian Armed Forces launched the cross-border offensive on Aug. 6, according to Smirnov.
MORE: Zelenskyy acknowledges push into Russia to put 'pressure on the aggressor'Putin said Russia will give "an appropriate response" to Ukraine and that "all the goals facing us will be achieved, undoubtedly."
"[It] looks like the enemy seeks to improve its negotiating positions in the future," Putin said during the operational meeting. "But what kind of negotiations can we talk about with people who indiscriminately target civilians, civilian infrastructure, and try to create a threat to nuclear power facilities? What can we even talk about with them?"
The Russian Nuclear Agency Rosatom claimed that Ukrainian forces attacked the Russian-occupied Zaporizhzhia Nuclear Power Plant in southeastern Ukraine on Sunday, hitting its cooling systems in drone strikes and causing a fire.
Ukraine, however, is claiming that Russia started the fire at the power plant. A Ukrainian intelligence source, speaking on the condition of anonymity, told ABC News the Russians set fire to a large pile of tires to create the fire. The source interpreted it as an attempt to frame Ukraine and to send a warning amid its ongoing incursion into Russia.
Amid the incursion, small Ukrainian units have been spotted in villages northeast toward the Kursk nuclear power station, which is located roughly 80 miles from the border, according to accounts from Russian military bloggers. Russia has beefed up security at the plant, though most analysts believe it is still too far for Ukrainian troops to reach.
The Russian Defense Ministry said Monday that additional forces and systems are being delivered to build up a Russian group of forces and form reserves in the Kursk region.
"The military communications service has organized the delivery of additional forces and systems to reinforce a group of forces and form reserves. Soldiers, military hardware, ammunition and other supplies required for combat operations and comprehensively supporting troops are being transported," it said.
MORE: At least 14 dead, 43 injured in strike on Ukrainian shopping mall: OfficialsSpecialists of the logistics units of the northern group of forces are working to "repel the attempted Ukrainian military incursion into the territory of the Russian Federation," it said.
Ukrainian President Volodymyr Zelenskyy addressed the Kursk offensive during an address Monday, saying Ukraine now controls areas where the Russian army had in recent weeks launched strikes on Ukraine's Sumy region.
"Therefore, our operations are purely a security matter for Ukraine, the liberation of the border area from the Russian military," he said.
He also said he expects Ukraine's minister of defense and diplomats to work on getting permission from Ukraine's partners to use long-range weapons against Russia.
"This is something that can significantly advance the just end of this war, as well as save thousands of Ukrainian lives from Russian terror," he said. "It is only fair to destroy Russian terrorists where they are, where they launch their strikes from -- Russian military airfields, Russian logistics. We see how useful this can be for bringing peace closer. Russia must be forced into peace if Putin wants to continue waging war so badly."