House representatives Josh Gottheimer and Emanuel Cleaver asked the Trump administration yesterday to provide more details on the recent seizure of cryptocurrencies belonging to major terrorist groups, according to news outlet The Hill.

Two weeks ago, the US Justice Department said the government had seized over 300 cryptocurrency accounts linked to terrorist outfits al-Qaeda, ISIS, and al-Qassam. It was termed the “largest-ever terrorist seizure of cryptocurrencies” by authorities and valued at “millions of dollars.”

But Cleaver, the chairman of the House Financial Services Subcommittee and Gottheimer, a member of the subcommittee—both belonging to the Democratic party—have since requested Treasury Secretary Steven Mnuchin and Attorney General William Barr to brief the subcommittee on the now-concluded operation.

“It is vital that Members of the Subcommittee on National Security, International Development and Monetary Policy receive a briefing, at the appropriate classification level, on this action, the largest ever seizure of online terrorist financing, from the Department of Justice, the Department of the Treasury on this investigation,” Cleaver and Gottheimer wrote, according to the report.

They added that the Treasury Department should provide an “assessment” of its efforts to impede bad actors targeting the broader US financial system using tools like cryptocurrencies.

“This will further inform the Subcommittee on what legislative actions we should be undertaking to provide regulators and law enforcement the proper resources and tools to continue to address the illicit use of cryptocurrency and disrupt terrorist organizations’ financial networks,” they wrote.

In a statement, Gottheimer said that foreign terrorist organizations like ISIS and al Qaeda were constantly evolving and using tactics to threaten the functioning of everyday life. He called for added security measures that must be implemented to combat such risks.

Terrorist groups have turned to cryptocurrencies in the past few years for the accessibility and anonymity provided by the assets ahead of cash and bank transfers. They have also adopted newer methods—the seizure earlier this month had gained cryptocurrencies by using the coronavirus pandemic as an excuse to raise funds from unsuspecting crypto users.

But while Bitcoin and other cryptocurrencies regularly come in the legal crosshairs for their apparent terrorist links, research suggests fiat money remains the largest source currently for all types of terrorist financing.