Russian President Vladimir Putin has warned NATO of 'serious danger' if the US-led military alliance enters the Ukraine war. Putin said that Russia has more nuclear warheads than all NATO nations combined. According to the Arms Control Association, Russia has a total stockpile of around 6,250 nuclear warheads as of January 2021, while the US has over 5,500, and two other NATO member states, Britain and France, have about 220 and 290 nuclear warheads, respectively. Watch this video to know more.