Ukrainian drones struck a key military airfield in Russia's Lipetsk region, forcing authorities to declare a state of emergency in another Russian region this week in the face of Kyiv's ongoing cross-border offensive.

Ukrainian forces targeted the airfield in Lipetsk — roughly 300 kilometers (186 miles) from the border with Ukraine — on Thursday night, hitting warehouses and a number of unspecified objects in the vicinity of the airport, Ukraine's General Staff of Command said in a Google-translated Telegram post.

"Several sources of ignition were recorded, a strong fire broke out and multiple detonations were observed," the Ukrainian military added, noting that Su-34, Su-35 and MiG-31 aircraft are based at Lipetsk.

Over a spate of Google-translated Telegram updates, Lipetsk Governor Igor Artamonov said a "massive" drone attack had damaged an energy infrastructure facility, leading to power supply disruptions and to the announcement of a state of emergency in the municipal district.

"At the moment, there are 9 people on the list of victims. All are receiving the necessary assistance," Artamonov said in a later Google-translated Telegram update, without detailing the state of those who had suffered injuries.

"The enemy is striking civilians in Kursk and Belgorod, today they massively attacked our region with drones. We will not be afraid, we will not give in, but we are not going to risk the lives of our people," he added.

CNBC could not independently verify developments on the ground.

This is the second imposition of a state emergency in a Russian region, as Kyiv continued its largest incursion on enemy soil since the start of Moscow's full-fledged invasion in February 2022. Earlier in the week, the Ukrainian offensive led to the evacuation of thousands of people and a state of emergency being announced in Kursk. Ukraine did not formally acknowledge the raid.

Kursk was still reporting missile danger alerts as of Friday, according to Google-translated Telegram updates from regional Governor Alexei Smirnov, who said the local situation remained "difficult."

Moscow has continued its own advances, with a Russian missile hitting a supermarket in the town of Kostiantynivka in the front-line Ukrainian region of Donetsk on Friday. At least 10 people were killed and 35 others were injured as a result, according to Minister of Internal Affairs Ihor Klymenko in a Google-translated Telegram update.

Kyiv's cross-border incursion is unlikely to mark an attempt to occupy Russian territory, but is more likely a counterattack against similar offensives carried out by Moscow on Ukrainian soil, particularly in the Kharkiv region.

The attack against the Lipetsk airfield comes after Ukraine's military last Saturday said it carried out a strike on Russia's Morozovsk airfield in the Rostov region, claiming it had hit warehouses with ammunition locally. In the same offensive, the Ukrainian force said it had also targeted a number of oil depots, and fuel and lubricant storage facilities in Rostov, Kursk and Belgorod.

"Russian combat aircraft must be destroyed wherever they are, by all effective means. Hitting Russian airfields is also quite fair," Ukrainian President Volodymyr Zelenskyy said in a Google-translated Telegram update on Aug. 3, following the Morozovsk strike.

On Thursday, the Kyiv leader signaled his administration's first acknowledgement of the cross-border offensive, stating in his nightly address that "Russia brought the war to our land, and it should feel what it has done." 

Asked whether Ukraine's Kursk incursion aligned with Washington's position — which allows Kyiv to use U.S.-supplied weapons for defensive purposes — deputy U.S. Pentagon press secretary Sabrina Singh said, "It is consistent with our policy and we have supported Ukraine from the very beginning to defend themselves against attacks that are coming across the border and for the need for crossfires."

"So they are taking actions to protect themselves from attacks that are coming from a region that are within the U.S. policy of where they can operate, you know, our weapons, our systems, our capabilities," she said.

Correction: Su-34, Su-35 and MiG-31 aircraft are based at Lipetsk. An earlier version misstated the type of aircraft based there.