NATO member Poland scrambled fighter jets close to the alliance's border with Ukraine, its military said, after Russia launched fresh overnight strikes and the U.S. shut the doors of its embassy in Kyiv over fears of large-scale attacks from Moscow.
The Polish military said early on Thursday that "Polish and allied aircraft have begun operating in our airspace" after Moscow attacked Ukrainian territory, including in the west of the country.
Warsaw's armed forces "activated all available forces and resources," including scrambling fighter jets and putting ground-based air-defense systems and radars on "the highest state of readiness," the military said.
Several regional authorities in western Ukraine, including in Lviv and the Volyn region bordering Poland, issued air alerts overnight.
Kyiv's air force said Russia had attacked the central city of Dnipro with a an intercontinental ballistic missile, as well as one of its Kinzhal hypersonic missiles and seven Kh-101 cruise missiles. Ukrainian air defenses intercepted six of the Kh-101 missiles, with the remaining three missiles not causing significant damage, the air force said.
Russia's Defense Ministry had not commented at the time of writing.
Russian attacks have occasionally spilled over into NATO members like Poland and Romania, which border chunks of western and southern Ukraine, when Moscow has targeted its neighbor's western regions.
Earlier, the U.S. shut its embassy in the Ukrainian capital after it "received specific information of a potential significant air attack" on Wednesday.
Kyiv' GUR military intelligence agency separately said information spreading among Ukrainian citizens about a huge Russian attack on Wednesday was "fake."
In his evening address on Wednesday, Ukrainian President Volodymyr Zelensky said the "information frenzy," including the spread of "panic messages around—all this benefits only Russia."
The previous day, Ukraine had used American-made long-range ballistic missiles on Russian soil for the first time since U.S. officials said President Joe Biden had greenlit the move after many months of refusing to do so.
Russia said on Tuesday that it had recorded the first Ukrainian strike using the U.S.-made Army Tactical Missile System, or ATACMS, against its soil in the border Bryansk region.
"ATACMS fragments fell on the technical territory of a military facility in the Bryansk region, a fire broke out, it was extinguished," the Russian Defense Ministry said.
Several British outlets also reported that Ukraine had used U.K.-supplied long-range Storm Shadow cruise missiles against Russian territory for the first time.
NATO nations had scrambled fighter jets over the weekend after Moscow carried out a large-scale aerial attack on Kyiv's energy infrastructure across the war-torn country.
Moscow launched "a massive, combined attack" of around 120 missiles and 90 drones across Ukraine, Zelensky said in a statement early on Sunday. Russia's Defense Ministry said it had carried out a "a massive strike with high-precision, long-range air- and sea-based weapons and strike drones" in the early hours of Sunday.
Moscow targeted Kyiv's "critical energy infrastructure facilities that supported the operation of Ukraine's military-industrial complex and enterprises producing military products," the Russian government said. "All planned targets were hit."
"Unfortunately, some facilities sustained damage from direct hits and falling debris," Zelensky said.