Federal agents have arrested some 750 people across the United States in a crackdown on Mexican drug cartels, US Attorney General Eric Holder has announced.
Among them were 52 people arrested on Wednesday in California, Minnesota and Maryland in raids targeting the powerful Sinaloa cartel, he said.
Agents also seized 23 tonnes of drugs in the 21-month operation.
A 2008 justice department report found Mexican traffickers were the biggest organised crime threat to the US.
Most of the cocaine available in the US is smuggled via the US-Mexican border, while Mexican drug traffickers control most of the US drug market.
Mexican smugglers are also increasingly working with US gangs, the report found.
The Sinaloa cartel is one of four main Mexican drug-trafficking groups, the others being the Gulf cartel, the Tijuana cartel and the Juarez cartel.
The US Congress has authorised the spending of $US1.6 billion to confront the threat of drug trafficking and organised crime from Mexico and Central America.
So far, $US197 million has been released for military and law enforcement training and equipment in Mexico.
Some 6,000 people were killed last year in Mexico in violence linked to organised crime. Mexican media reported that by mid-February this year there had already been 1,000 killings.