The Mexican army says soldiers have seized 229 kilograms (505 pounds) of opium paste hidden in buried containers in the mountains of southern Guerrero state.

The army said Tuesday that the opium paste would have produced about 20 kilograms of processed heroin. It said the seizure was made 10 days earlier in a mountainous region of Guerrero state known for opium growing.

Troops found buried buckets and bags of the gummy paste extracted from poppy flower bulbs. Three rifles and almost 300 rounds of ammunition were found nearby.

An increase in opium growing and trafficking has triggered a rise in violence in Guerrero state, where a drug gang is alleged to have killed and incinerated 43 college students in September.