The Mexican army found 70 of the 76 containers of cyanide that were stolen from a delivery truck earlier this month.
The containers, each holding 100 kilogrammes of the deadly substance that was to be delivered to a mining company, were found at the bottom of a ravine west of Mexico City, the defence ministry said.
Another six containers with 600 kilogrammes (1,320 pounds) of sodium cyanide remained missing, the ministry said. The United States had expressed concern that the missing cyanide might end up in the hands of terrorists.
Initially, 96 containers of cyanide were aboard the delivery truck that was stolen when its driver stopped to help a motorist who was having car trouble on a road in Hidalgo. The truck driver told police he was caught off guard by three armed men who took off with his vehicle and its cargo.
About 1,500 police officers and soldiers searched central Mexico for the deadly chemical and the thieves.
On May 16th, the truck and 20 containers of the stolen chemical were found abandoned in the central state of Puebla.
AFP