CHICAGO (AP) — Federal prosecutors in Chicago say the leaders of a powerful Mexican drug cartel once planned a military-style attack on a U.S. or Mexican government building.

Prosecutors described the allegations in documents filed Thursday in the case against Vicente Zambada, who they say is a top lieutenant in the Sinaloa cartel. He’s in custody in Chicago awaiting trial.

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Prosecutors say the cartel members were upset about American law enforcement interfering with their drug business and sought dozens of American-made weapons for an attack in Mexico City.

Prosecutors say a cartel leader said the attack was intended to “send the gringos a message.”

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The possible targets included government buildings, an embassy or consulate or media outlet.

The plot was allegedly hatched during a 2008 meeting at a mountaintop compound in Mexico.

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