What exactly are the weapons?
The annual presidential address to the parliament is usually a rather boring affair in Russian Federation, but President Putin has certainly managed to make an impression with the speech delivered on March 1, 2018.
Putin promises that Russia's new missiles will stay close to the ground and travel too quickly for ground defenses to react. The 1972 treaty was one of the most important Cold War agreements because missile defense was believed to be destabilizing in how the two countries calculated nuclear strategies. The Russian leader also voiced concerns about a new USA nuclear doctrine, saying that Russia's own doctrine was defensive and only envisaged the use of nuclear weapons in response to an attack.
How anxious should we be?
Experts can argue about whether Putin oversold the new weapons' supposed invulnerability to US missile defense systems, especially those that, like the weapons themselves, may still be in development.
Development on the weapon predates the fall of the Soviet Union.
The Trump administration interprets Russian statements and actions over the past several years, including its annexation of the Crimea and military incursions into eastern Ukraine, as requiring a stronger US nuclear deterrent.
"At the end of 2017 it wasn't the rocket itself that was tested, but a mock-up". "You listen to us now".
Why is Putin doing this now?
Russian opposition leader Alexei Navalny, who was controversially been barred from elections over a criminal conviction, mocked the video demonstrations as "cartoons" on Twitter.
If he had boasted of Russia's achievements in education or healthcare, voters would have been able to see the deception themselves, Navalny said in a YouTube video.
President Putin rebuffed accusations by Western media outlets that he was starting a new arms race.
Meanwhile, Russians are showering the Defence Ministry with proposed names for the country's new nuclear weapons, relishing the online contest announced by Mr Putin in his state-of-the-nation address on Thursday.
The State Department expressed concern over the Russian video, along with the Putin speech, which targeted the US. This was not a "confrontational" speech, said Mr Peskov, but a demonstration of Russia's potential for technological advance.
What will the impact be?
The spat came as relations between the powers lie frozen at post-Cold War lows over the Syria and Ukraine conflicts and accusations that Moscow interfered in the United States presidential election in 2016.
The Kremlin Saturday criticized Washington's extended sanctions against Moscow as illegal and harmful.