KYIV, Ukraine (AP) -- Russia declared a "federal-level" emergency in the Kursk region following a large-scale incursion from Ukraine and sent reinforcements there on Friday, four days after hundreds of Ukrainian troops poured across the border in what appeared to be Kyiv's biggest attack on Russian soil since the war began.

Meanwhile, a Russian plane-launched missile slammed into a Ukrainian shopping mall in the middle of the day, killing at least 12 people and wounding 44 others, authorities said.

The mall in Kostiantynivka, in the eastern Donetsk region, is located in the town's residential area. Thick black smoke rose above it after the strike.

"This is another targeted attack on a crowded place, another act of terror by the Russians," Donetsk regional head Vadym Filashkin said in a Telegram post.