A U.S. official on Thursday confirmed to Fox News Digital that Ukrainian authorities were briefed ahead of the "experimental Intermediate-range ballistic" attack that this type of weapon may be used against it in order to help them prepare for such an attack.

Russian President Vladimir Putin confirmed the attack Thursday evening local time in an address to the nation and said it was in direct response to the U.S. and U.K. jointly approving Ukraine’s use of Western-supplied long-range missiles to target Russia.

It remains unclear if there were any casualties in the attack on the city of Dnipro, which was originally reported as an Intercontinental Ballistic Missile (ICBM), and which would have marked the first time such a weapon had been used during a time of war, sending panic across the globe. 

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Putin and U.S. sources have since confirmed the strike was not an ICBM, but the Kremlin chief also claimed that the weapon used poses a significant challenge for Western nations. 

"The missiles attack targets at a speed of MACH 10. That's 2.5 miles per second," Putin said according to a translation. "The world's current air defense systems and the missile defense systems developed by the Americans in Europe do not intercept such missiles."

Fox News Digital could not immediately verify whether the U.S. or its NATO allies are capable of defending against this latest missile, dubbed the Oreshnik. 

But according to one U.S. official, Putin may be playing up his abilities in a move to intimidate the West and Ukraine. 

"While we take all threats against Ukraine seriously, it is important to keep a few key facts in mind: Russia likely possesses only a handful of these experimental missiles," the official told Fox News Digital. "Ukraine has withstood countless attacks from Russia, including from missiles with significantly larger warheads than this weapon.

"Let me be clear: Russia may be seeking to use this capability to try to intimidate Ukraine and its supporters, or generate attention in the information space, but it will not be a game-changer in this conflict," the official added. 

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Following President Biden’s position reversal this week to allow Ukraine to use U.S.-supplied long-range Army Tactical Missile Systems (ATACMS) against the Russian homeland, Kyiv immediately levied strikes against a military arsenal in the Russian region of Bryansk, more than 70 miles from Ukraine’s border. 

While Ukrainian troops are the ones to officially fire the sophisticated missiles, the weapons system still relies on U.S. satellites to hit their target – an issue Putin touched on in his unannounced speech Thursday. 

"We are testing the Oreshnik missile systems in combat conditions in response to NATO countries' aggressive actions against Russia. We will decide on the further deployment of intermediate-range and shorter-range missiles depending on the actions of the U.S. and its satellites," he said.

Putin claimed Russia will alert Ukrainian citizens of an impending attack like the strike he carried out on Thursday, though it remains unclear if he issued a warning to the Ukrainians living in Dnipro. 

The Kremlin chief said the "defense industry" was targeted, though images released by the Ukrainian ministry of defense showed what appeared to be civilian infrastructure was also caught in the fray. 

The Pentagon on Thursday confirmed that Russia informed the U.S. of the impending attack, which corresponds with information obtained by Fox News Digital, but it is unclear if Moscow clarified which Ukrainian city was the intended target.

A U.S. official told Fox News Digital that the U.S. is committed to helping Ukraine bolster its air defense systems and has done so already by supplying Ukraine with hundreds of additional Patriot and Advanced Medium-Range Air-to-Air Missiles.