Security forces in Colombia have seized a large shipment of cocaine bound for Mexico in the port city of Cartagena,

Security forces in Colombia have seized a large shipment of cocaine bound for Mexico in the port city of Cartagena, authorities said on Monday.

The Colombian Navy said the shipment of about 12 tons of cocaine was found hidden in containers loaded with a type of brown sugar known as panela and was discovered with the help of sniffer dogs.

No suspects were detained in connection with the seizure of the narcotics shipment, which incidentally is the largest of its kind in Colombia in recent years.

The Navy said the shipment, which originated in the Valle del Cauca region in south-west Colombia, was destined for the Mexican state of Veracruz on the Gulf coast.

Valle del Cauca region is considered to be stronghold of one of the country's most powerful drug gangs, the Rastrojos. The seized shipment is believed to belong to the Rastrojos gang.

The main drug gangs operating in the region are mostly made up of members of former right-wing paramilitaries. They are now said to have taken over control of the drug trade from the once powerful drug cartels and Leftist rebel groups.

Monday's seizure comes just weeks after the Colombian authorities identified criminal gangs that are increasingly taking control of drug trade as the country's biggest security threat, and pledged more resources to capture gang members.