- US ambassador not surprised by Putin’s threat of nuclear deterrence | TheHillThe Hill
- Putin puts nuclear deterrent on ‘special alert’ during Ukraine conflict – BBC NewsBBC News
- Live updates: Russia invades UkraineCNN
- Kharkiv invaded by Russian troops as residents hide in bomb shelters | USA TODAYUSA TODAY
- NATO chief calls Putin alert order irresponsible, cites ‘dangerous rhetoric’Reuters