Mexico’s navy has said it arrested 23 people in its largest-ever drugs bust, seizing over eight tonnes of illicit cargo in an operation off the country’s south-western Pacific coast.

“Navy personnel seized 8,361 kilograms of illicit cargo, which represents the largest amount of drugs seized in a maritime operation, unprecedented in history,” a statement from the ministry of the navy said on Friday.

It did not specify the type of the drugs, but said they were valued at 2.099bn pesos ($105m).

The navy also seized 8,700 litres of fuel and six boats of the coast near Lazaro Cardenas, in Michoacan state, and further south off the coast of Guerrero state.

“The 23 detainees, who were read their rights, as well as the six boats, the presumed drugs and the fuel were handed over to the competent authorities for integration into the corresponding investigation,” the navy added.

The drugs were distributed in six small boats and one of the vessels was a submersible, which implied a “complex” action on the part of the sailors, the ministry added.

The largest drug seizure in Mexico’s history was 23 tonnes of Colombian cocaine in November 2007. According to the navy, Friday’s announcement represents the largest amount ever seized in a maritime operation.

The latest raid reported on Friday was carried out “days ago” by surface units backed by a helicopter, the ministry said.

On 23 August, authorities reported they had impounded about seven tonnes of drugs in two separate operations in the same area of the country.

The Mexican navy, which conducts surveillance operations on a permanent basis, has discovered all kinds of drug shipments, including one of cocaine stuffed in 217 barrels of chilli sauce in 2016.

The US has pushed Mexico to ramp up its efforts to stop drug trafficking, while Mexico has pressured the US to do more to stem the flow of firearms to criminal groups across the border into Mexico.

With Reuters and Agence France-Presse