Mexican police have found a stolen truck that was carrying dangerous radioactive material the UN said could provide an ingredient for a "dirty bomb," a government official has said.
The truck was found on Wednesday close to where it was stolen outside Mexico City, said the official, but could not confirm whether the cargo was aboard.
The truck was stolen on Monday while it was taking the radioactive material cobalt-60 from a hospital in the northern city of Tijuana to a radioactive waste-storage centre, Mexican officials and the UN agency said earlier.
The vehicle was seized when the driver stopped at a gas station in the town of Temascalapa, 35km northeast of Mexico City.
Mardonio Jimenez, from National Nuclear Security commission has told Al Jazeera the container was found open and that whoever opened it has been exposed to lethal doses of radiation and will require immediate medical attention.
Authorities are looking into clinics in the area.
The army has sealed the area while authorities implement a procedure to retrieve the open container.
Mexican officials say the thieves were most likely common criminals unaware of the truck's radioactive cargo.
Truck hijacking is common in Mexico and the theft occurred in the State of Mexico, which is not a drug cartel stronghold.
"Our suspicion is that they had no idea what they had stolen. This is a area where robberies are common," Fernando Hidalgo, spokesman for the Hidalgo state prosecutor, said earlier.
Apart from peaceful medical and industrial applications, experts say, cobalt-60 can also be used in a dirty bomb in which conventional explosives disperse radiation from a radioactive source.
The International Atomic Energy Agency, which has stepped up calls on member states to tighten security to prevent nuclear and radioactive materials from falling into the wrong hands, made no mention of any such risk in its statement on Wednesday.
The IAEA also did not give details on how much radioactive material was in the vehicle when it was seized.
Cobalt-60 is used in the treatment of cancer.