In the largest single strike at Mexican drug operations in the U.S., federal officials on Thursday announced the arrests of more than 300 people in raids across the country aimed at the newest and most violent cartel.

La Familia has earned a reputation for dominating the methamphetamine trade and displaying graphic violence, including beheadings.

U.S. officials said the cartel, based in the state of Michoacan, in southwestern Mexico, has a vast network pumping drugs throughout the United States, specializing in methamphetamine.

The arrests took place in 38 cities, from Boston to Seattle and Tampa, Fla., to St. Paul, Minn., in 19 states.

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Attorney General Eric Holder pledged to keep hitting La Familia and the cartels responsible for a wave of bloodshed in Mexico. He said the U.S. would attack them at all levels, from the leadership to their supply chains reaching far into the United States.

"To the extent that they do grow back, we have to work with our Mexican counterparts to cut off the heads of these snakes, to get at the heads of the cartels, indict them, try them, if they're in Mexico, extradite them to the United States," Holder said at a news conference.

Michele Leonhart, who heads the Drug Enforcement Administration, said La Familia's power has grown quickly, in part due to its quasi-religious background. DEA officials say the cartel professes a "Robin Hood mentality" of aiding the poor by stealing from the rich. Some drug proceeds are used to give bibles and money to the poor, according to investigators.

The Obama administration has directed more agents, resources and money to fight the cartel's presence along the Mexico-U.S. border. But the arrests over the past two days occurred far beyond that region.

"The problem is not just along the southwest border, it is all over our country now," said Kenneth Melson, head of the Bureau of Alcohol, Tobacco, Firearms, and Explosives.

In Dallas alone, 77 people were charged by a number of different federal and local law enforcement agencies.

On Wednesday and Thursday, more than 3,000 federal agents and police officers carried out arrests in more than a dozen states, as part of a long-running effort that has netted nearly 1,200 arrests over almost four years.

The suspects face a combination of federal and state charges.

In the latest legal assault on La Familia, a New York grand jury has indicted an alleged cartel leader, Servando Gomez-Martinez. He is linked to one of the more brazen acts of cartel violence.

In July, after a dozen Mexican police officers were found murdered, officials say Gomez-Martinez publicly proclaimed his membership in La Familia and said the cartel was locked in a battle with Mexican police.

Many of the new charges are centered on the cartel's methamphetamine distribution, but other charges involve cocaine and marijuana, the officials said.

The officials said states where arrests were made or charges filed include Arizona, California, Colorado, Florida, Georgia, Kansas, Illinois, Massachusetts, Minnesota, Mississippi, Missouri, Oklahoma, Nevada, New York, North Carolina, South Carolina, Tennessee, Texas, and Washington state.