Nigerian troops operating in the oil-rich southern region have destroyed 51 illegal refineries during the fight against "economic saboteurs and other criminal elements," a military spokesperson said on Thursday.

Speaking at a media briefing on ongoing military operations across the country in Abuja, Benard Onyeuko, the military spokesperson, said troops from the Operation Delta Safe deactivated the sites, which were identified in the southern states of Rivers, Abia, Cross River, Bayelsa, Akwa Ibom and Imo.

Onyeuko told reporters troops have continued to conduct operations in the south-south zone to thwart the activities of economic saboteurs and other criminal elements.

"In the course of the operations, troops discovered and deactivated 51 illegal refining sites," he said, adding 23 suspects related to illegal refining were arrested together with some weapons and ammunition.

Activities of oil pipeline vandalization and oil theft were frequently reported in the biggest oil producer in Africa, causing huge economic losses and even claiming lives every year.