The U.S. Attorney's Office for the Eastern District of Texas announced on Wednesday that the country has filed charges against 21 people for participating in international cryptocurrency money laundering networks.

In addition to the seizure and forfeiture of millions of dollars' worth of cash and cryptocurrencies, law enforcement officials said that an annual flow of over $300 million in laundered transactions had been halted.

"These arrests are just the beginning. We are committed to bringing each of the remaining perpetrators to justice," Secret Service Special Agent William Smarr said.

"This case proves that we can track these people down and charge them," Secret Service Resident Agent Bill Mack told CNBC's Eamon Javers.

The U.S. Attorney for the Eastern District of Texas also provided further information about some of the people named in indictments or who had pled guilty.

Randall Rule, 71, and Gregory Nysewander, 64, were indicted in federal court for allegedly utilizing bitcoin to launder more than $2.4 million in proceeds from wire fraud and mail fraud schemes.

John Khuu, 27, was charged in federal court with money laundering conspiracy. Khuu is accused of laundering more than $5 million in illegal revenues from counterfeit medications and prohibited substances in the United States.

The charges were released as part of "Operation Crypto Runner," a joint effort between U.S. Attorney Brit Featherston of the Eastern District of Texas, the Secret Service, and the U.S. Postal Inspection Service.

In particular, elderly people were the goal of the initiative, according to Featherston.

Federal law enforcement has taken other significant actions in the crypto space before.

Tornado Cash, which the federal government alleged has been used to launder more than $7 billion in cryptocurrency since its launch, was sanctioned by the U.S. Treasury in August.

The government claims that Tornado Cash encourages illegal activities, including "facilitation of heists, ransomware schemes, fraud, and other cybercrimes," even if other users use it only to safeguard their privacy.

Developer of Tornado Alexey Pertsev was detained in Amsterdam shortly after the penalties were implemented, according to Dutch law enforcement, for allegedly aiding in "concealing criminal financial flows and facilitating money laundering."

Tornado has been utilized in several high-profile cryptocurrency heists this year, including a $615 million theft of tokens from Ronin, a network supporting the nonfungible token game Axie Infinity, and a $100 million attack on U.S. business Harmony. Security researchers linked both to the Lazarus Group, a North Korean state-backed hacking group.

The Treasury's Office of Foreign Assets Control (OFAC) has placed Tornado Cash and its related crypto wallet addresses on its "Specially Designated Nationals" list.