US authorities have reportedly obtained warrants to seize planes owned by Russian oligarch Roman Abramovich.
A Department of Justice official said on Monday that Abramovic flew to Russia without a licence required following US sanctions imposed on Moscow in response to its invasion of Ukraine.
The US moved to seize a $60 million Gulfstream and a $350 million aircraft, which are thought to be among the most expensive private airplanes in the world.
The US Department of Commerce also filed administrative charges against Abramovich, who it said in February named his Russian children the beneficiaries of the "shell entities" that owned the Boeing 787 Dreamliner and Gulfstream G650 ER aircraft, but that he continued to control them.
The charges come as authorities in the US seek to pressure business leaders close to Russian President Vladimir Putin to convince the President to end the invasion of Ukraine.
Abramovich has not personally been sanctioned by the United States.
The former Chelsea owner was sanctioned by the UK government earlier this yearGetty images
The Commerce Department said that the Gulfstream flew from Istanbul to Moscow on March 12 and the other aircraft flew from Dubai to Moscow on March 4. These both came after export restrictions were put into effect on February 24.
Both planes were made in the US, which meant a licence was needed to fly them to Russia.
Federal prosecutors said in their seizure warrant that no licences were applied for or issued for the planes.