Polish authorities have arrested a Russian national suspected of planning to kill a Ukrainian-American dual citizen in Warsaw, Prime Minister Donald Tusk said Thursday. Tusk said the suspect was allegedly recruited by Russia's secret services, and described the case as the first time someone acting on Moscow's orders had sought to attack an American citizen on NATO territory. The prime minister did not provide further details about the timing of the arrest or the identity of the suspect. The Ukrainian-American citizen was reportedly the intended target of the alleged plot, which was thwarted before it could be carried out. Tusk's statement highlights growing concerns about Russian espionage and sabotage activities across Europe since the war in Ukraine began. Poland, a key NATO member and a major supporter of Ukraine, has frequently accused Russia of conducting covert operations on its soil. Russian officials have not yet commented on the allegation. The arrest marks a significant security development for NATO, as it underscores the alliance's exposure to suspected Russian intelligence operations targeting foreign nationals on member territory.