Russian President Vladimir Putin has placed the country's nuclear deterrent on high alert. The announcement was made after Russia faced a barrage of sanctions and aggressive reprisals from the U.S., NATO, and the European Union over its attack on Ukraine.

U.S. officials said Putin's order to place Russia's deterrence forces, including those capable of launching nuclear attacks, on high alert presented a serious threat to the world. Officials said Putin is rapidly escalating the war with his "dangerous rhetoric."

Russia's attack in Ukraine, which is the largest assault ever made on a European state since World War II, has not panned out as planned as Russian forces are being repelled in several major cities.

Days after it began its "special operations" in Ukraine, Western nations immediately began to take political, strategic, corporate, and economic actions against Russia with the aim of crippling the nation's economy. The EU announced Sunday that it would supply weapons to Ukraine, the first time the 27-nation bloc had assisted a country at war.  

Putin justified his actions by claiming that Ukraine was being controlled by "Neo-Nazis" and was now a threat to Russia's national security. During a speech on Sunday, Putin slammed Western and NATO leaders for their aggressive statements against Russia. He said that not only are these countries taking "unfriendly measures" against Russia, but they are continually making aggressive statements.

Last week, Putin had seemingly referred to his country's nuclear capability as Russian forces moved towards Ukraine. He warned that any country that will stand in its way will face consequences that they "have never encountered in their history."  

The EU's foreign policy chief, Josef Borrell, said Russia was clearly threatening a nuclear attack on any country that would support Ukraine. Borrell added that a Russian victory in Ukraine might result in more "special operations" that will threaten other neighboring nations.

The U.S. Ambassador to the United Nations, Linda Thomas-Greenfield, called on Putin to "tone down" his "dangerous rhetoric," particularly when it comes to talks about using Russia's nuclear weapons. The UN recently conducted an emergency meeting involving all 193 member states to discuss the Ukrainian crisis.

Ukraine's health ministry said at least 352 people, including 14 children, have been killed since Russia began its campaign last week. The ministry said that about 1,684 people had been wounded in various clashes in and around major Ukrainian cities. Russia confirmed that some of its soldiers had been killed during the initial attack, but officials claimed that its losses were far lower than those in Ukraine.