Vladimir Putin is understood to have carried out three tests on a hypersonic glide vehicle known as “Avangard” that is capable of carrying a nuclear warhead, according to sources familiar with US intelligence reports.
The Russian leader boasted earlier this year his military might was “invincible”.
The first two tests were a success while the third in October last year was seen as a failure.
Mr Putin is expected to carry out a fourth test over the summer.
The director of the Missile Defence Project at the Centre for Strategic and International Studies, Thomas Karako, starkly warned the weapon could “attack the gaps” in US military defences.
He stated: “These kinds of boost glide vehicles attack the gaps in our missile defence system.
“There’s no time like the present to modify our current missile defence posture.
“It is unfortunate that we have let Russia come this far.”
The horrifying weapon is designed to sit on top of an intercontinental ballistic missile – Russian SS-19s are understood to have carried the glide vehicle.
Avangard is incredibly precise and conducts itself at a frighteningly quick speed, the sources added.
Russia is believed to have been developing the weapon for over 30 years.
The glide vehicle can travel five times the speed of sound which equates to roughly one mile per second.
Putin watches MIG-31K interceptor jets at Victory Parade
But Vladimir Putin has previously claimed the highly capable hardware can travel at 20 times the speed of sound and strikes “like a fireball”.
He added: “I want to tell all those who have fuelled the arms race over the last 15 years, sought to win unilateral advantages over Russia, introduced unlawful sanctions aimed to contain our country’s development: You have failed to contain Russia.”
The leader sent a frightening message to Washington by iterating Moscow’s capabilities were “not a bluff”.
Mr Putin is expected to carry out a fourth test over the summer
Russia is readying an ‘invincible’ missile that Donald Trump is currently unable to defend against
Air Force General John Hyten, commander of US Strategic Command, previously told the Senate Armed Services Committee the US has no defences against a hypersonic weapon.
He stated: “We don’t have any defence that could deny the employment of such a weapon against us.
“Both Russia and China are aggressively pursuing hypersonic capabilities.”