US Customs and Border Patrol officers confiscated more than half a ton of fentanyl — over 4 million pills — in the largest seizure of the drug in agency history, officials announced this week.

The jaw-dropping quantity of deadly opioids was discovered by CBP officers at the border Port of Lukeville in Arizona when they stopped a 20-year-old driver of a pickup truck that was hauling a sports recreation vehicle on a trailer.

After noticing several “anomalies” in the frame of the trailer, officers pulled the truck off to the side for further inspection,” the agency said.

A K9 team revealed 234 packages of drugs stashed in the frame containing roughly 4 million blue fentanyl pills.

 “This is the largest fentanyl seizure in CBP’s history, and reflects our unwavering determination to protect our nation and to disrupt the criminal activities of ruthless drug cartels,” Troy Miller, CBP Senior Official Performing the Duties of the Commissioner, said in a statement. 

“Every day, CBP officers and agents are on our front line, using their keen instincts and the latest technology to prevent deadly drugs from entering our country and poisoning our communities.”  

On July 12, CBP agents at the same port of entry seized 272 pounds of methamphetamine when a 45-year-old Mexican citizen was also driving a pickup truck towing a trailer.

Again with the help of a K9 team CBP agents discovered 39 packages of the drug and an additional five pounds of cocaine, the agency said.

Between both major drug busts, officials say the estimated street value is more than $12.6 million. Both men were arrested.

“This is an enormous amount of dangerous drugs that officers at the Port of Lukeville prevented from reaching communities throughout the United States,” said Guadalupe Ramirez, Director of Field Operations, Tucson Field Office.

The Post has reached out to CBP for additional information on the arrests.

The Port of Lukeville is about 150 miles southeast of Tucson.