New Delhi, July 30 -- Two Customs and Border Protection officers pleaded guilty this month to allowing vehicles filled with illegal drugs to enter the U.S. from Mexico, federal prosecutors said Monday.

The pair texted "a secret emoji-based code" to let Mexican traffickers know which inspection lanes they were manning at the Tecate and Otay Mesa border crossings, the U.S. Attorney's Office said in a statement. Prosecutors said when the drug-laden vehicles arrived, the officers would wave them through.

Officers Jesse Clark Garcia, 37, and Diego Bonillo, 30, each pleaded guilty to multiple charges, including conspiracy to import controlled substances such as cocaine, methamphetamine and heroin, the statement says.

As part of his plea deal...