The US and its allies on Saturday moved to block certain Russian banks’ access to the SWIFT international payment system in further punishment of Moscow as it continues its military assault against Ukraine.

The measures, which will include restrictions on the Russian central bank’s international reserves, will be implemented in the coming days, the nations said in a joint statement that also vowed further action to come.

“We will hold Russia to account and collectively ensure that this war is a strategic failure for Putin,” the leaders of the European Commission, France, Germany, Italy, Great Britain, Canada and the United States wrote.

“Even beyond the measures we are announcing today, we are prepared to take further measures to hold Russia to account for its attack on Ukraine.”

The move comes after the US and its allies slapped sanctions this week on major Russian banks as well as on President Vladimir Putin, among others, as Moscow’s forces pushed into the heart of Ukraine toward Kyiv.

“As Russian forces unleash their assault on Kyiv and other Ukrainian cities, we are resolved to continue imposing massive costs on Russia. Costs that will further isolate Russia from the international financial system and our economies,” said Ursula von der Leyen, president of the European Commission, the European Union’s executive.

The actions are aimed at preventing Putin from using $630 billion in central bank foreign currency reserves in the invasion of Ukraine and to defend a plunging rouble.

Cutting Russian banks out of the SWIFT system — the world’s main international payments network — deals a blow to Russian trade and makes it harder for Russian companies to do business.

“Putin’s government is getting kicked off the international financial system,” a senior US administration official said.

SWIFT, or the “Society for Worldwide Interbank Financial Telecommunication”, is a secure messaging system that facilitates rapid cross-border payments, making international trade flow smoothly and transferring trillions of dollars each year in what has become the principal mechanism for financing international trade.

“We are engaging with European authorities to understand the details of the entities that will be subject to the new measures and we are preparing to comply upon legal instruction,” SWIFT said in a statement.

The US official told reporters that if one of the banks cut off from SWIFT wants to make a payment with a bank outside of Russia, it will likely need to use a phone or fax machine.

But the official said most banks worldwide would likely stop all transactions with Russian banks removed from the network.

The US and its allies will finalise the list of banks that will be cut off from SWIFT, the official said, adding that banks already under US and European sanctions would be the first ones considered.

Japan joins West

Japanese Prime Minister Fumio Kishida says Japan has decided to join the US and European nations in cutting key Russian banks from SWIFT, reports AP.

Japan will also freeze assets of Russian President Vladimir Putin and other top Russian officials, while sending $100 million in emergency humanitarian aid to Ukraine, Kishida told reporters.

BP to exit Rosneft

BP said on Sunday it would exit its 19.75 per cent stake in Russian oil giant Rosneft after Russia’s invasion of Ukraine amid growing pressure from the British government. The decision to abandon the Rosneft holding will result in charges of up to $25 billion at the end of the first quarter, BP said in a statement. BP acquired its Rosneft shareholding in 2013 as part of the $12.5bn sale of a stake in TNK-BP. BP chief executive Bernard Looney and his predecessor Bob Dudley will both step down from the Rosneft board.