The action to be rolled out on Friday will hit "Russia, its enablers, and its war machine," a Treasury spokesperson told AFP.

The official added that these sanctions will be introduced from both the Treasury and State Department.

This will be the "largest single tranche since the start of Putin's further invasion of Ukraine," the Treasury said, referring to Russian President Vladimir Putin.

Since Russia invaded neighboring Ukraine in February 2022, Washington and its allies have imposed a host of sanctions, targeting Moscow's revenue and military industrial complex.

Among the efforts has been a price ceiling enacted by the United States and allies, aimed at slashing Moscow's revenues from exports of oil and petroleum products.

To reduce funding for the war while still ensuring supplies to the global market, a coalition involving the Group of Seven leading economies, the European Union and Australia had set a price cap of $60 per barrel of Russian crude.

Due to the cap, Russia had the choice to either sell discounted oil to coalition countries or invest in building an alternative ecosystem.

In recent months, the coalition announced plans to tighten compliance for the price ceiling.

- Sanctions 'against Putin' -

The fresh sanctions to be unveiled Friday come after Kremlin opposition leader Alexei Navalny died last week in an Arctic prison.

US President Joe Biden earlier reaffirmed plans for sanctions, saying they would be "against Putin, who is responsible for his death."

On Thursday, Biden said he had met privately in California with Navalny's widow and daughter.

He told reporters after meeting with Yulia and Dasha Navalnaya in San Francisco that Putin's late opponent was "a man of incredible courage."

Russian authorities announced on February 16 that Navalny, 47, had died suddenly in custody.

Since then, a series of European governments also summoned Russian diplomats.

On Thursday, the US government marked the upcoming two-year anniversary of Russia's invasion as well by unsealing charges against a series of wealthy Russians to help cut the "flow of illegal funds that are fueling" Moscow's war.

Attorney General Merrick Garland said the Justice Department "is more committed than ever" to cutting off the funds, and to holding accountable those who continue to enable the war.

The White House has said as well that Washington would soon impose new sanctions on Iran over its backing for Russia's invasion.

"In response to Iran's ongoing support for Russia's brutal war, we will be imposing additional sanctions on Iran in the coming days," National Security Council spokesman John Kirby told journalists.

He said authorities are prepared to go even further if Iran sells ballistic missiles to Russia.

Ukrainian forces are running short of ammunition as they fight invading Russian troops, with additional funding for Kyiv held up in the US Congress.