Mexican Police Find Stolen Truck With Radioactive Cargo The truck's cargo container was empty, an official said.

Dec. 4, 2013 -- Mexican authorities said a stolen truck carrying "extremely dangerous" material used in medical treatment was located today. The nuclear waste, however, had been removed.

Using radioactive detectors, authorities located 40 grams of Cobalt-60 about a half-mile away from the truck's container, according to Juan Eibenschutz, director of the Mexican Nuclear Agency.

A spokesperson for the attorney general's office told ABC News the truck had likely been abandoned when authorities located it in the town of Hueypoxtla, located about 90 miles from Mexico City.

No arrests have been made.

The truck was transporting Cobalt-60 from a hospital in the northern city of Tijuana to a radioactive waste storage facility when it was stolen in Tepojaco near Mexico City on Monday, the International Atomic Energy Agency said in a statement. Cobalt-60 is a radioactive isotope and was being used in radiotherapy.

"At the time the truck was stolen, the source was properly shielded. However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged," the IAEA said in the statement.

There was no indication from officials that the truck was headed for the U.S.

U.S. law enforcement and Department of Homeland Security officials said earlier this week that they were aware of the theft and working closely with Mexican authorities, a U.S. official briefed on the situation told ABC News.

Border officials were armed with radiation detection devices in the event the person who stole the material tried to cross into the U.S., the official said.