Border Patrol agents found 200 pounds of cocaine and methamphetamine inside the gas tank of a bus at the San Ysidro port of entry over the weekend.
The drugs are worth more than $3.2 million, according to the U.S. Customs and Border Protection (CBP).
On Sunday, around 9:30 p.m., agents at the San Ysidro port of entry were alerted to a commercial bus that was waiting to be inspected.
During a secondary inspection, agents found anomalies with the bus's gas tank and discovered 98 packages from inside.
CBP said the packages contained cocaine and methamphetamine.
The driver of the bus, a 50-year-old man who is a Mexican citizen with a B1/B2 Visa, was arrested and turned over to Homeland Security Investigations agents.
The drugs and the bus were seized by agents.
They also put an immigration detainer on the driver so that he will be returned to the custody of the Department of Homeland Security (DHS) after the judicial process.