A truck carrying an extremely dangerous radioactive substance has been stolen in central Mexico, the U.N. nuclear agency said Wednesday.

The International Atomic Energy Agency said the truck was carrying cobalt-60, used for radiotherapy treatment to combat cancer. An IAEA statement Wednesday said the truck was stolen Monday while taking the material to a radioactive waste storage center from the northern city of Tijuana.

The IAEA said the heist occurred in Tepojaco, a town near Mexico City, and describes the load as “extremely dangerous” if damaged or removed from its protective shielding. It said Mexican authorities are searching for the material.

The statement provided no further details.

The National Commission for Nuclear Safety and Safeguards of Mexico’s Secretary of Energy said that the radioactive material found inside the medical equipment is properly shielded and poses no risk as long as its container is not fractured or otherwise altered.

(AP)