Members of an elite Mexican anti-drug unit passedinformation to a drug cartel in exchange for thousands of dollars,prosecutors say.
They said police agents and senior officials gave sensitive information to the Beltran Leyva organization.
Assistant Attorney General Marisela Morales said those involved had received up to $450,000 (£290,000) a month from the cartel.
They allegedly told the cartel about potential raids and surveillance.
Five officials in the anti-crime unit were arrested, four of them weeks ago.
The passing of information is alleged to have lasted for much of the past four years.
‘Spy’ claims
The security breach is being described as the worst case ofinfiltration by traffickers of the Mexican law enforcement system in adecade.
The country’s Attorney General Eduardo Medina Mora said: “Weconducted investigations which showed that members of the deputyattorney general’s office were providing classified information aboutoperatives working against the Beltran Leyva organisation to members ofthat organisation in exchange for large amounts of money.”
One worker said he spied from within the US embassy on the DrugEnforcement Administration, one Mexican official told the AssociatedPress news agency.
The US embassy said it did not comment on internal matters.