The United States took immediate action on Monday to ban U.S. dollar transactions with Russia’s central bank and completely block the Russian direct investment fund, senior administration officials said, pointing to some of the most powerful ways of Russia to mitigate the effect of the sanctions.

The measures are aimed at preventing Russia from accessing an “emergency fund” that officials say Moscow hoped to use during the invasion of Ukraine. Instead of using reserves to cushion the ruble’s fall, Russia will no longer be able to access the funds it holds in US dollars.

The sweeping new sanctions, passed alongside Germany, France, the United Kingdom, Italy and Canada, the European Union and others, come as the Russian economy is already free fall.

“No country is immune from sanctions,” a White House official said. “Putin’s war chest of $630 billion in reserves only matters if it can be used to defend his currency, namely by selling those reserves in exchange for buying the rouble.”

“After today’s actions, this will no longer be possible, and the Russian fortress will be exposed as a myth.”

In a phone call with reporters Monday morning, a senior administration official said the move was “the culmination of months of planning and preparation in our respective governments through technical, diplomatic and political channels, including included at higher levels”.

“We were prepared and that’s what allowed us to act within days, not weeks or months of Putin’s escalation,” the official said.

“Our strategy, to put it simply, is to ensure that the Russian economy regresses while President Putin decides to continue his invasion of Ukraine,” said a second senior administration official.

To mitigate the impact of the sanctions on energy consumers in the United States and Europe, the Treasury Department will exempt most energy-related transactions from the sanctions, which is an important exception to the sanctions.

One official called the ongoing sanctions “a vicious feedback loop triggered by Putin’s own decisions and accelerated by his own aggression.”

The sanctions also completely block the Russian Direct Investment Fund and its CEO, Kirill Dmitriev. The officials said they were “symbols of deep-rooted Russian corruption and global influence peddling”.

“Today’s actions represent the largest taken by the US Treasury against an economy of this size and assets of this size,” another official said. “What also makes this asset important is not just the number of assets or the size of the country we are targeting, but the speed with which our partners and allies have worked with us to implement this response.”

Asked about possible additional sanctions against Belarus, which appears poised to step up its role in Russia’s invasion of Ukraine, an official said the United States was monitoring developments “very carefully”. situation and that the sanctions against Belarus “would continue to increase”.