Russia has claimed that it plans to deploy its new intercontinental ballistic missiles, dubbed 'Satan 2', by this autumn.
The Sarmat ICBMs can travel up to 11,000 miles and carry ten or more nuclear warheads capable of destroying an area the size of the UK.
Dmitry Rogozin, head of the Roscosmos space agency, confirmed Russia intends to deploy the deadly weapons this year.
Russia reported its first test launch on Wednesday, and Western military experts say more will be needed before the missile can be deployed.
This week's test came after years of delays due to funding and technical issues.
It marks a show of strength by Russia at a time when the war in Ukraine has sent tensions with the US and its allies soaring.
Some fear Russia could even use the missiles against Ukraine if the Kremlin fails to achieve its war aims.
Leigh Turner, the former British ambassador to Ukraine, said: "If Russia is visibly losing this war, it could be that Putin would authorise their use."
Mr Rogozin said in an interview with Russian state TV that the missiles would be deployed with a unit in the Krasnoyarsk region of Siberia, about 1,860 miles east of Moscow.
He said they would be placed at the same sites and in the same silos as the Soviet-era Voyevoda missiles they are replacing, something that would save "colossal resources and time".
The launch of the "super-weapon" was a historic event that would guarantee the security of Russia's children and grandchildren for the next 30-40 years, Mr Rogozin added.
When tested on Wednesday, Russian President Vladimir Putin said the missile had the "highest tactical and technical characteristics" and was capable of overcoming all anti-missile defence systems.
Putin added: "It has no analogues in the world and won't have for a long time to come.
"This truly unique weapon will strengthen the combat potential of our armed forces, reliably ensure Russia's security from external threats and provide food for thought for those who, in the heat of frenzied aggressive rhetoric, try to threaten our country."
The Russian Ministry of Defence said: "Sarmat is the most powerful missile with the longest range of destruction of targets in the world, which will significantly increase the combat power of our country's strategic nuclear forces."
Western fears about nuclear war have increased since Putin launched his invasion of Ukraine.
In a speech on the day of Russia's invasion, Putin made a terrifying reference to the prospect of nuclear war.
He said that any attempt to get in Russia's way would lead to "such consequences that you have never encountered in your history".
United Nations Secretary-General Antonio Guterres said: "The prospect of nuclear conflict, once unthinkable, is now back within the realm of possibility."
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