Russian President Vladimir Putin signed an updated military doctrine Friday that listed the North Atlantic Treaty Organization as the top military threat and, for the first time, presented the possibility of using conventional precision weapons “as part of strategic deterrent measures.” The doctrine released by the Kremlin describes NATO’s expansion plans, military buildup near Russian borders and the alliance’s empowerment with “global functions realized with violation of international law” as main threats against Russia’s national security, according to the Associated Press.

The document also says Russia could use nuclear weapons in response to nuclear or other weapons of mass destruction used against the nation or its allies. It said nuclear weapons will be used if a potential military attack — whether nuclear or conventional — “threatens the very existence” of Russia. The previous military doctrine, signed by Putin in 2010, had named NATO’s expansion a top risk and outlined the use of nuclear weapons; but tensions between Russia and the West over Ukraine have raised the stakes, according to Reuters.

NATO denied posing any threat to Russia or any nation, according to the Associated Press. "Any steps taken by NATO to ensure the security of its members are clearly defensive in nature, proportionate and in compliance with international law," NATO spokeswoman Oana Lungescu said in a statement Friday. "In fact, it is Russia's actions, including currently in Ukraine, which are breaking international law and undermining European security."

Russia has been outraged since Ukraine’s parliament voted to drop the country’s neutral status on Tuesday and take steps to formally align itself with the West — an indication that Kiev will pursue NATO membership. Russian Deputy Defense Minister Anatoly Antonov has threatened to cease cooperation with NATO if Ukraine joins the Western military alliance, Reuters reported.

"NATO countries pushed Kiev to this counterproductive decision, trying to turn Ukraine into a front line of confrontation with Russia," Antonov told the Russian news agency Interfax on Wednesday. "If this decision in the future takes on a military character [accession to NATO], then we will respond appropriately. Then there will be a complete severing of ties with NATO, which will be practically impossible to repair.”

Former President of the Soviet Union Mikhail Gorbachev reportedly said “serious meetings are needed” to resolve the situation in Ukraine. “All of us, both politicians and society, are worried over what is going on in Ukraine. What has always been our inborn trait is that our government is supporting people who are in trouble, is receiving thousands of such people, regardless of our own troubles,” Gorbachev told Russia's Tass news agency on Friday, while presenting his new book, “After the Kremlin.”

Russia’s relations with the West have taken a nosedive this year and echo sensibilities of the Cold War times. NATO had increased its military presence in Eastern Europe after Russia annexed Ukraine’s Black Sea peninsula of Crimea in March. The military alliance has accused Russia of fueling a pro-Russian rebellion in Eastern Ukraine, following the overthrow of a Kremlin-backed president in Kiev; Russia has denied the allegations. As a result, the United States and the European Union have imposed strict economic sanctions against Russia, causing a near economic collapse for the former Soviet Union.