Nigeria's military says two Russians who were kidnapped two months ago escaped from their captors and have been rescued.

A military spokesman, Lieutenant Colonel Sagir Musa, says the two men escaped on foot from a camp where they were being held. They spent five days wandering through wetlands in the Niger Delta region, until a patrol of Nigerian soldiers found them Thursday and brought them to safety.

The Russians worked for an aluminum smelting plant in the port town of Ikot Abasi in the state of Akwa Ibom.

Kidnappings and other attacks are common Nigeria's oil-rich south.

Nigeria remains Africa's largest exporter of crude oil although production has declined about 20 percent during the last three years, primarily due to disruptions caused by violence and kidnappings.

Unrest has spread eastward in recent months, from Rivers and Bayelsa states toward Nigeria's border with Cameroon.

The main militant group in the area, the Movement for the Emancipation of the Niger Delta or MEND, recently cancelled a unilateral cease-fire in an angry response to what it said was an army attack on one of the group's hidden camps.

The militants say they are fighting for redistribution of the profits from Nigeria's oil industry, with more aid going to the country's impoverished residents. The government calls the militants common criminals.

Some information for this report was provided by AFP, AP and Reuters.