Investigators are searching for three armed men who made off with 275 pounds of gold, worth more than $4 million, after robbing an armored vehicle in North Carolina, according to news reports.

Two armed guards from TransValue told police they were transporting a shipment of precious metals between Miami and Massachusetts on Sunday night when their truck began having mechanical problems and pulled over on Interstate 95 in Wilson County, N.C., according to the Wilson Times.

The guards told police that’s when they were approached by three armed men driving a white van, according to the Times. The guards said the suspects forced them onto the ground before tying their hands behind their backs and walking the men into nearby woods, according to the Times. The victims said the suspects fled the scene with several barrels of gold.

NBC affiliate WITN reported that the truck “was an 18-wheeler, and the locks on the back doors appeared to have been cut or sawed off. The big rig is all white, except for having the company’s logo on the sides of the cab.”

“This is very rare,” Jesus Rodriguez, owner of TransValue, told the Times.

The victims were treated for minor injuries — scratches from the woods — according to the Times.

Shelley Lynch, a spokeswoman for the FBI’s Charlotte field office, told Fox News that agents are assisting local law enforcement and trying to determine whether a federal crime was committed.

Sunday’s heist, however large, doesn’t approach the largest theft in North Carolina history. That happened in 1997, “when $17 million in cash was stolen from the Loomis Fargo vault in Charlotte,” according to NBC affiliate WWLP. The perpetrator, David Scott Ghantt, was eventually arrested in Mexico, the station added.

TransValue, founded in 1992, specializes in transporting valuable jewels, cash, precious metals and gems in its armored trucks and is insured for $100 million, according to the company’s Web site.