WASHINGTON — Justice Department officials announced Tuesday the arrests of 150 people and the seizure of more than $30 million in an international investigation targeting drug trafficking on the darknet.

The sweep led to arrests in the United States, Great Britain, Germany and other countries, law enforcement officials said.

In addition to seizing $31 million in cash and digital currency, investigators also seized 45 handguns, Justice Department officials said.

“Since the onset of the COVID-19 pandemic, more people have turned to the darknet than ever before to buy drugs,” Deputy Attorney General Lisa Monaco told reporters.

Monaco said investigators focused particular attention on darknet vendors who were minting counterfeit pills that contained potentially fatal doses of fentanyl, methamphetamines and other illegal drugs. The darknet, an encrypted version of the internet that requires special tools to navigate, is a popular marketplace for illicit goods.

The operation “prevented countless lives from being lost to this dangerous trade in illicit and counterfeit drugs because one pill can kill,” Monaco said.

Many of the counterfeit pills were made to look like common prescription drugs, said Anne Milgram, the administrator for the U.S. Drug Enforcement Administration.

“We cannot stress enough the danger of these substances,” Milgram said. “These are the drugs that are driving the overdose crisis in America.”

The 10-month operation, which involved law enforcement officials in the U.S. and Europe, took place as drug overdose deaths have spiked. Last year, more than 90,000 people in the U.S. died of drug overdoses, a 30% increase over 2019, according to federal statistics.

Among those arrested in the operation was Jonathan Patrick Turrentine, a 39-year-old Sacramento, California, resident, who was indicted Thursday on federal charges of distributing controlled substances and one count of possession with intent to distribute and money laundering, according to the U.S. attorney’s office of the Eastern District of California. Turrentine’s lawyers did not respond to a request for comment.