RT/Moscow: The US pullout from the 1972 Anti-Ballistic Missile Treaty was a threat to Russia’s security and risked “zeroing” its nuclear arsenals, prompting Moscow to design unparalleled hypersonic projectiles, President Vladimir Putin said. Moscow, which claims primacy in the worldwide race to develop the ultra-fast weapons systems, faced an urgency to maintain strategic parity with its near-peer opponent Washington, the Russian president recalled on Saturday.

“The US withdrawal from the Anti-Ballistic Missile Treaty [ABM Treaty] in 2002 forced Russia to start developing hypersonic weapons,” Putin said while speaking over a video link to Gerbert Yefremov, a renowned engineer who played a lead role in designing an array of sensitive missile systems for the Russian military.
Al-Masdar News@TheArabSourcePutin says #Russia had to create Hypersonic Weapons after US’ pullout from ABM Treaty https://almasdarnews.com/article/putin-says-russia-had-to-create-hypersonic-weapons-after-us-pullout-from-abm-treaty/…#USA
Signed back in 1972, the ABM Treaty was instrumental in helping keep the equilibrium between Russian and American nuclear deterrents, until the 2002 pullout threatened to dramatically tilt the balance. No longer bound by the pact, the US rushed to deploy its ballistic missile shields, including close to Russian borders. From Canada, December 2019:

Moscow could not stand back and watch the new threat emerge, Putin continued.
We had to create these weapons in response to the US deployment of a strategic missile defense system, which in the future would be capable of virtually neutralizing, zeroing out all our nuclear potential.
Russian Exercises@RUSexercisesTASS: Putin said that the US withdrawal from the ABM treaty forced Russia to create hypersonic weapons https://tass.ru/armiya-i-opk/9501307
Russia also had to catch up with its prime rival on nearly every track, from building nuclear weapons to designing long-range bombers and intercontinental ballistic missiles.
Oliver Stone@TheOliverStonePutin’s words have been distorted in our #MSM as an aggression towards US. But #Putin outlines how the West has pushed #Russia to invent these systems b/c US has provoked nuclear tension with 2002 pull out from ABM treaty.5:26 PM · Mar 6, 2018
According to Putin, the need to play catch-up has always put the country “in a very difficult and even dangerous situation.” On certain occasions, “we were threatened but had nothing to respond,” he admitted.
He praised Yefremov’s contribution in creating hypersonic weapons, likening it to the Soviet nuclear program of the 1950s and 1960s.
For our country today, the embodiment of your concepts is undoubtedly comparable to implementing USSR’s nuclear and missile projects, which were carried out by outstanding Soviet scientists [Igor] Kurchatov and [Sergey] Korolev.
The modern-day advances in hypersonic technology turn the tide in Russia’s favor, Putin said. “Right now, for the first time in our modern history, Russia possesses the most modern types of weapons, which are many times superior in strength, power, speed and accuracy to previous and existing ones,” he explained.
I can’t breathe@KenartsTheKingUS withdrawal from ABM treaty & anti-missile system in Europe [“iranian threat”] gives Russia the self-defense right to break #INF treaty
Russia claims to be the first nation to have fielded a hypersonic weapon, the Avangard glide vehicle. Other projectiles, like the Kinzhal (Dagger) cruise missile and the Zircon anti-ship missile, are undergoing trials or said to be in the works.
In addition, the Russian military industry is on its way to designing an interceptor missile that will be able to shoot down adversary ultra-speed munitions. As part of the effort, it has recently rolled out a radar station designed to track over a thousand fast-moving targets, including those that are hypersonic.