A caller headdress connected the terms of Russian lipid volition "immediately chopped into Putin's astir important root of revenue," the US has said.
US Treasury Secretary Janet Yellen said the headdress - which was officially approved by Western allies connected Friday - came aft months of hard work.
The headdress stops countries paying much than $60 (£48) a tube for seaborne exports of Russian crude oil.
It is owed to travel into effect connected 5 December oregon soon after.
Low and medium-income countries that person been heavy impacted by precocious vigor and nutrient prices volition peculiarly payment from the cap, Ms Yellen said.
She said it volition besides further constrain Russian President Vladimir Putin's finances and "limit the revenues he's utilizing to money his brutal invasion".
"With Russia's system already contracting and its fund progressively stretched thin, the terms headdress volition instantly chopped into Putin's astir important root of revenue," she said successful a statement.
The terms headdress was enactment guardant successful September by the G7 radical of nations (the US, Canada, the UK, France, Germany, Italy, Japan and the EU) successful a bid to deed Moscow's quality to concern the warfare successful Ukraine.
The European Union approved the terms headdress - which needed the statement of each its subordinate states - connected Friday, aft persuading Poland to backmost it.
Poland announced its enactment aft being reassured the headdress would beryllium kept astatine 5% little than the marketplace rate.
It had been reported that the EU wanted to acceptable the headdress astatine $65-70 but this was rejected by Poland arsenic good arsenic Lithuania and Estonia arsenic excessively high.
Warsaw had wanted the worth to beryllium arsenic debased arsenic imaginable and had held retired portion it examined an accommodation mechanics which would support the headdress beneath the marketplace complaint arsenic the terms of lipid changed.
In a associated statement, the G7, the EU and Australia said the determination to enforce a terms headdress was taken to "prevent Russia from profiting from its warfare of aggression against Ukraine".
British Chancellor Jeremy Hunt said the UK volition not waver successful its enactment and volition proceed to look for caller ways to "clamp down connected Putin's backing streams".
The statement of a terms headdress comes conscionable days earlier an EU-wide prohibition connected Russian crude lipid imported by oversea comes into force, besides connected 5 December.
The terms headdress - which is meant to impact lipid exports worldwide - is meant to complement that.
Countries that motion up to the G7-led argumentation volition lone beryllium permitted to acquisition lipid and petroleum products transported via oversea that are sold astatine oregon beneath the terms cap.
Ukraine's occidental allies besides program to contradict security to tankers delivering Russian lipid to countries that bash not instrumentality to the terms cap. This volition marque it hard for Russia to merchantability lipid supra that price.
Russia denounced the scheme, saying it would not proviso those countries which enforced a terms cap.
Senior Russian person Leonid Slutsky, who chairs the overseas affairs committee, told Tass quality bureau the EU was jeopardising its ain vigor information with the cap.
Before the war, successful 2021, much than fractional of Russia's lipid exports went to Europe, according to the International Energy Association. Germany was the largest importer, followed by the Netherlands and Poland.
But since the war, EU countries person been desperately trying to alteration their dependency. The US has already banned Russian crude oil, portion the UK plans to signifier it retired by the extremity of the year.
Though the measures volition astir surely beryllium felt by Russia, the stroke volition beryllium partially softened by its determination to merchantability its lipid to different markets specified arsenic India and China - who are presently the largest azygous buyers of Russian crude oil.