Mexican authorities have recovered dangerous radioactive cancer-treating material that was being transported on a truck stolen at a gas station, authorities said Tuesday.

They did so with a remote controlled robot that placed it in a truck with a container covered with concrete, the National Security Commission said.

The truck was stolen last Wednesday in the town of Hueypoxtla in central Mexico.

Five men have been arrested. Four of the men are accused of stealing the truck while the fifth suspect bought it.

The suspects were hospitalized last week in the central state of Hidalgo with signs of radiation exposure, but they were given the all clear after 24 hours.

The truck was carrying an obsolete cancer-treating medical device that was on its way to a radioactive waste storage facility when it was stolen at a service station in Hidalgo on December 2.

The truck and device were found 65 kilometers (40 miles) north of Mexico City after a two-day manhunt.

The machine contained 60 grams of cobalt-60, a highly radioactive isotope that experts say could be used to make a crude "dirty bomb".

The theft prompted the International Atomic Energy Agency to issue an alert for "extremely dangerous" material and US authorities to keep tabs on the situation.

But Mexican authorities believe the thieves had merely planned to sell the device as scrap metal.