Federal authorities launched a broadside against Mexico’s Jalisco New Generation drug cartel on Wednesday, revealing that they had arrested hundreds of those associated with the gang as part of a six-month operation to attack its U.S.-based infrastructure.

The first phase of the operation — which officials dubbed “Project Python” — culminated with a nationwide roundup of the gang’s associates Wednesday, when law enforcement authorities arrested more than 250 people and seized almost 600 kilograms of drugs and more than $1.7 million in money and assets, acting Drug Enforcement Administration head Uttam Dhillon said.

Dhillon said that since the operation began Sept. 1, authorities had arrested more than 700 people associated with the gang on drug trafficking-related crimes, and seized more than 20,000 kilograms of drugs and $22 million of money and other assets.

“This operation is one of the largest, concentrated actions against a single criminal organization in many years,” Dhillon said. “By removing mid- and high-level members, we inhibit CJNG’s ability to regenerate and to continue to threaten our communities and neighborhoods with their deadly drugs.”

CJNG is an acronym that refers to the cartel.

Wednesday’s sweep is the latest in a series of aggressive moves the Justice Department has taken to target the Jalisco New Generation Cartel, which they consider among the world’s most dangerous, and other Mexican drug gangs. Last month, the son of the group’s leader, was extradited from Mexico to face prosecution in federal court in Washington, D.C., and his sister was then taken into custody when she showed up at his bond hearing.

Rubén Oseguera González, better known as “El Menchito,” and his sister, Jessica Johana Oseguera Cervantes, are the children of Nemesio Ruben Oseguera Cervantes, or “El Mencho,” the cartel’s leader. U.S. officials have offered a $10 million reward for information that leads to his arrest, and the Justice Department announced Wednesday it had brought a superseding indictment charging him with running a continuing criminal enterprise.

El Mencho’s son, whom the Justice Department has described as second-in-command of the gang, was arrested by Mexico’s army in 2015, though he had for years avoided being sent to the United States. He has pleaded not guilty to charges of distributing cocaine and methamphetamine and using a firearm to facilitate drug trafficking. His sister also has pleaded not guilty to violating a U.S. ban on transacting with designated drug trafficking entities and individuals.

Project Python was aimed not at high-profile targets, but rather, mid- to high-level associates in the United States, officials said. Assistant Attorney General Brian Benczkowski said investigators will use the data they collected as part of Project Python to “identify and map out the cartel’s logistical nodes and pathways.” The Jalisco New Generation Cartel, he said, moves multiple drugs in the United States, but is a particularly prolific producer and distributor of methamphetamine. He said it also is “the most well-armed” cartel in Mexico, responsible for significant violence there.

The Justice Department has long taken an aggressive posture toward Mexican cartels, and in December, Attorney General William P. Barr visited Mexico and told officials he was concerned about the government’s response to soaring violence in that country. Since that trip, about 40 people alleged to be involved in organized crime have been sent to the United States for prosecution.

They include Ismael Zambada Imperial, the son of another major trafficker, as well as José María Guizar Valencia, a leader of the violent Zetas organization — a ­rival of sorts to Jalisco New Generation.

Benczkowski declined to say if Barr was more satisfied with Mexico’s efforts to combat cartels than he was in December, but said Justice Department officials enjoy a “strong and productive” relationship with their counterparts in that country.

Last year, the Justice Department won a conviction against perhaps its most high-profile cartel target: Joaquín Archivaldo Guzmán Loera, or “El Chapo,” the leader of the Sinaloa cartel whose dramatic prison escapes made him an internationally known celebrity. He was sentenced in July to life in prison.