21.“The United States was pre-notified briefly before the launch, through nuclear risk reduction channels,” Defense Department Deputy Spokesperson Sabrina Singh said.The warning, sent 30 minutes before the launch, was also confirmed by Kremlin spokesperson Dmitry Peskov.The U.S. had previously alerted Ukraine and its allies that Russia might test such an experimental missile.In the early hours of Nov. 21, a country-wide air raid alert sounded due to the threat of ballistic missiles, and later, the launch of several Russian Tu-95MS bomber aircraft.According to Ukraine's Air Force, the attack targeted the city of Dnipro using a number of different missile types.Late on Nov. 21, Putin said in a televised address that the attack was a test of Russia's "newest missile," an IRBM called "Oreshnik.