U.S. Customs and Border Protection officers made the largest seizure of meth and fentanyl in the history of the Andrade Port of Entry in California, officials announced. 

Officers encountered a 37-year-old female U.S. citizen driving a 2016 pickup truck from Mexico into the United States on Sunday afternoon, the border agency said Monday. 

Upon further inspection with an imaging system, officers discovered "irregularities" in the vehicle's gas tank and a K-9 team positively alerted agents to narcotics being present, the agency said.

Officers ultimately found 46 packages of fentanyl pills weighing nearly 54 pounds with an estimated street value of nearly $750,000 and 30 methamphetamine packages weighing about 32 pounds with an estimated street value of more than $200,000.

Law enforcement seized the vehicle and turned the driver over to the custody of U.S. Immigration and Customs Enforcement and Homeland Security Investigations.