The Mexican military seized a fentanyl shipment worth an estimated $1.87 billion just yards from the U.S. border last week.

The shipment included 63.8 kilograms of pure fentanyl and nearly 30,000 pills made with the drug, according to the newspaper El Financiero.

The pure fentanyl by itself would have a street value of $1.2 billion, according to Drug Enforcement Agency numbers reported by El Financiero.

The shipment was intercepted Aug. 19 at a Mexican Army checkpoint near San Luis Rio Colorado, a city across the Colorado River from Yuma, Arizona.

President Trump visited Border Patrol installations in Yuma Tuesday before heading to Phoenix for a campaign-style rally.

Fentanyl is a synthetic opiate that is much cheaper to produce than heroin. It has taken over a large part of the black market that's fueled the opioid crisis.

A kilo of fentanyl costs about $2,000 to produce and can reach a street value of up to $20 million USD.

According to the United States-China Economic and Security Review Commission, China is the primary source for fentanyl smuggled into the United States.

The largest fentanyl seizure to date had been a 45 kilograms load impounded in San Diego in 2016.