US President Joe Biden's administration has imposed fresh sanctions on Russia in response to Moscow's
Among the punitive measures announced on Friday by three cabinet-level departments were those from the Department of the Treasury that designated "14 persons in Russia's military-industrial complex, including two international suppliers, three key leaders of Russia's financial infrastructure, immediate family members of some of senior Russian officials, and 278 members of Russia's legislature" for enabling the referendums that resulted in Moscow claiming the regions of Donetsk, Luhansk, Kherson and Zaporizhzhia as Russia's sovereign territory, reports Xinhua news agency.
"The Treasury Department and US government are taking sweeping action today to further weaken Russia's already degraded military industrial complex and undermine its ability to wage its illegal war," said Treasury Secretary Janet Yellen.
While announcing the sanctions, the Department said that it it has also issued new guidance that "warns of the heightened sanctions risk that international actors outside of Russia would face for providing political or economic support to Russia as a result of its illegal attempts to change the status of Ukrainian territory".
Meanwhile, the Commerce Department added 57 companies located in Russia and the Crimean Peninsula - which Moscow declared as its territory in 2014 following a referendum -- to the so-called Entity List, designating them as export control violators.
In addition, the Commerce Department issued new guidance warning that "the US' export controls on Russia can be applied to entities in third countries that seek to provide material support for Russia's and Belarus's military and industrial sectors".
The State Department has imposed visa restrictions on Russian national Ochur-Suge Mongush for torturing a Ukrainian prisoner of war, according to a statement by Secretary of State Antony Blinken.
Visa restrictions are also being applied to another "910 individuals, including members of the Russian Federation military, Belarusian military officials, and Russia's proxies for violating Ukraine's sovereignty, territorial integrity, and political independence", Blinken said.
In response to Russia's move, Biden said on Friday that the US "will rally the international community to both denounce these moves and to hold Russia accountable", adding Washington "will continue to provide Ukraine with the equipment it needs to defend itself".
Noting that his administration on Wednesday announced an additional round of security assistance to Kiev worth $1.1 billion, the President said he looked forward to "signing legislation from Congress that will provide an additional $12 billion to support Ukraine".
Earlier on Friday, Russian President Vladimir Putin signed the "accession treaties" with the regions' Moscow-installed leaders at a ceremony in the Kremlin's opulent St George's Hall.
Watched by members of the political elite, he declared the regions would "forever" be part of Russia, the BBC reported.
Kiev, meanwhile, reacted by launching a new, fast-track bid to join the NATO alliance.
Flanked by his Prime Minister and the Speaker of Parliament, Ukrainian President Volodymyr Zelensky said his country had long been a "de-facto" member of the security bloc, and accused Moscow of redrawing borders "using murder, blackmail, mistreatment and lies".
"We are taking our decisive step by signing Ukraine's application for accelerated accession to NATO," the BBC quoted Zelensky as saying.
Russia's move has received widespread international condemnation.
While NATO Secretary General Jens Stoltenberg called the move "the most serious escalation since the start of the war", EU Commission President Ursula von der Leyen said "the illegal annexation proclaimed by Putin won't change anything... Ukrainian land and will always be part of this sovereign nation".
French President Emmanuel Macron pledged to "stand by Ukraine in order to deal with Russian aggression and to enable Ukraine to recover its full sovereignty across its entire territory".
In response, the UK banned has export of almost 700 goods to Russia that are critical to manufacturing production.
The EU Commission unveiled proposals to impose a cap on the price of Russian seaborne oil, while also imposing a ban on the bloc's citizens serving on the boards of Russian companies.