The unidentified suspect was stopped as part of a routine check at the U.S. Customs and Border Protection Station in the northbound lanes of the 5 Freeway around 1:15 a.m.
Officials say the 54-year-old driver was wearing a suit and tie when stopped. Agents said they became suspicious when the suspect claimed he was a U.S. citizen.
When a background check uncovered the suspect was a Mexican national, agents arrested the suspect for making a false claim to U.S. citizenship and searched his 2011 Hyundai Elantra.
Cardboard boxes laden with 53 cocaine packages were uncovered in the trunk and on the backseat weighing 670 pounds. The cocaine was estimated to be worth $6.7 million.
"Our checkpoints serve as part of the Border Patrol's layered enforcement approach to secure our borders and prevent smugglers from using our highways to transport people or contraband into the county," said San Diego Sector Chief Patrol Agent Paul Beeson. "The illicit-drugs we prevent from being sold on our streets not only keeps our communities safer but will deny transnational criminal organizations those expected proceeds."
The suspect arrested in connection with the drug bust was handed over the federal Drug Enforcement Agency.