U.S. officials unveiled a sweeping set of legal actions against Russian oligarchs and their allies on Thursday, as the Biden administration aims to intensify the financial pressure on President Vladimir Putin over his invasion of Ukraine.

Justice Department officials announced the arrests of two “facilitators” of one sanctioned Russian oligarch, while also moving to seize two luxury condominiums in Miami held by another Russian oligarch already under U.S. sanctions. The Justice Department also filed a separate indictment against an official in connection with an alleged scheme to operate a luxury yacht owned by a sanctioned Russian oligarch, and it highlighted a guilty plea related to money laundering on behalf of other sanctioned Russian entities.

The flurry of legal actions come as the United States looks for ways to respond to Putin over the sudden death last week of Russian opposition leader Alexei Navalny in an Arctic prison colony. White House officials said earlier this week that the administration will release new sanctions against Russia over Navalny’s death, although it is unclear how effective these financial penalties could prove. The United States has targeted Russia’s economy with economic penalties over the war in Ukraine for roughly two years, since the beginning of the invasion, and yet Russia’s economy grew substantially last year and is expected to continue to grow this year.

Despite the sanctions push, the Kremlin continues to reap billions of dollars from energy sales that the Western allies, wary of spiking gas prices, have not moved to cut off fully. Some experts predicted that stringent U.S. penalties on Russian oligarchs would prompt them to turn on Putin and endanger his hold on power, but, at least so far, those hopes have not materialized. Washington has led its international allies in imposing a price cap on the sales of Russian oil, but some analysts say it must be more rigorously enforced.

“Sanctions against Russian oligarchs push in the right direction, but are not enough,” said Simon Johnson, an MIT economist. “The missing element is the enforcement of the Russian oil price cap, to really squeeze the Kremlin’s revenues.”

The actions announced Thursday were spearheaded by the Justice Department’s KleptoCapture task force, which was formed in March 2022 to target Russian oligarchs as a main plank of the Western response to the invasion of Ukraine. To date, the task force has filed 70 criminal charges against individuals and five charges against corporate entities, while moving to restrain or forfeit approximately $700 million in assets, according to Deputy Attorney General Lisa Monaco.

U.S. officials, briefing reporters on Thursday, said roughly $6 million in seized Russian assets have been transferred to Ukraine, primarily for help with veterans of the war.

“Since the onset of Russia’s brutal and unprovoked invasion of Ukraine, the Justice Department has used every tool in our arsenal — including our international partnerships — to target the criminal actors and activity propping up Vladimir Putin, his henchmen, and his illegal war,” Monaco said in a statement.

The Justice Department said authorities in the U.S. District Court for the Southern District of New York unsealed charges against three people, including sanctioned oligarch Andrey Kostin, and arrested two people accused of being Kostin’s “facilitators.” The United States also filed a civil forfeiture complaint to seize two Miami luxury condo properties, located at the Ritz Carlton in Bal Harbour and valued at $2.5 million, owned by sanctioned Russian oligarch Viktor Perevalov. Other charges included a new indictment against Vladislav Osipov on charges of bank fraud in connection with operating the Motor Yacht Tango, a 255-foot luxury yacht owned by sanctioned Russian oligarch Viktor Vekselberg.