U.S. Customs and Border Protection officers halted two attempts at smuggling mass amounts of liquid and crystal methamphetamine across the San Ysidro Port of Entry over the weekend, authorities said Monday.

A 27-year-old man entered the border crossing in a 1993 Ford pickup truck on Friday at 9 a.m. and was ordered to the inspection area, CBP officer Angelica De Cima said. During the inspection, a drug-sniffing dog alerted officers to the gas tank where they discovered 166 pounds of liquid meth inside.

In a separate attempt, a 22-year-old driver and his 19-year-old passenger were arrested early Monday after federal agents allegedly found 126 pounds of liquid and crystallized methamphetamine inside the gas tank of the vehicle in which they were traveling, according to De Cima.

They pulled into the inspection and processing station in a 1972 Ford pickup truck at about 4:45 a.m., according to Customs and Border Protection officials.

While looking over the vehicle, a CBP officer opened the gas tank and noticed that the fuel appeared unusual, according to U.S. Customs and Border Protection. Agents then removed the tank and found the illegal drug inside it, authorities said.

The men were arrested and booked into Metropolitan Correctional Center in downtown San Diego. Customs personnel seized the truck and the methamphetamine.

All arrested suspects were U.S. citizens.

The estimated value of the seized methamphetamine is $2.9 million.

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