The United States Department of Health and Human Services has spent $290 million on an anti-radiation treatment amid Russia's nuclear warnings, which President Joe Biden said created the highest risk level of nuclear "Armageddon" since the 1962 Cuban Missile Crisis.

The HHS confirmed the purchase of the drug Nplate from Amgen USA Inc, which is approved to treat blood cel injuries associated with acute radiation syndrome among adult and pediatric patients, according to a news release shared on Tuesday (October 4).

The drug was developed with support from the Biomedical Advanced Research and Development Authority (BARDA), which provided $290 in Project BioShield designated to purchase the supply of the drug.

During an appearance at a Democratic Senatorial Campaign Committee fundraiser on Thursday (October 6), Biden referred to Russian President Vladimir Putin as "a guy I know fairly well" who is "not joking when he talks about the use of tactical nuclear weapons or biological or chemical weapons."

“We have not faced the prospect of Armageddon since Kennedy and the Cuban Missile Crisis,” Biden added, suggesting Putin's threats are real “because his military is — you might say — significantly underperforming.”

In 1962, American officials discovered the Soviet Union had secretly deployed nuclear weapons to Cuba, which led to a 13-day showdown considered by experts to be the closest the world has ever come to nuclear annihilation.

Putin repeatedly made threats regarding the Kremlin's nuclear arsenal last month while announcing a partial military mobilization of 300,000 reservists in Moscow's ongoing invasion of neighboring Ukraine, during a rare, prerecorded television announcement last month, Reuters reported.

Putin claimed that Ukraine -- a country he ordered troops to invade earlier this year -- "wants to destroy our country" during the announcement.

"If the territorial integrity of our country is threatened, we will use all available means to protect our people - this is not a bluff," Putin said via Reuters.

Russia's defense minister Sergei Shoigu confirmed that 300,000 reservists with prior military experience would be called up as part of the partial mobilization.

The decision marked Russia's first mobilization since World War II and the biggest escalation since invaded Ukraine in February.

Ukraine and its Western allies said Putin's call for more troops signified that his invasion of the neighboring country was failing.

"Absolutely predictable appeal, which looks more like an attempt to justify their own failure," Ukrainian Presidential Adviser Mykhailo Podolyak told Reuters. "The war is clearly not going according to Russia's scenario."

Allies vowed to continue their support of Ukraine amid Putin's announcement.

Putin announced his country would conduct military operations in Eastern Ukraine during an NBC News translation of a speech addressing the Russian population in Moscow on February 24.

The announcement appeared to serve as the final action ahead of an attack by Putin and the Russian military, which the U.S. and European allies to the neighboring Ukraine have attempted to prevent from taking place through diplomatic discussions.