Forces of the two countries have annually carried out joint war games, with last year's 11-day Key Resolve and Foal Eagle exercise involving some 18,000 American troops and about 20,000 South Korean soldiers. Seoul and Washington claim the drill is a routine exercise to improve their combined military power, while North Korea insists it is a precursor to invasion.

"During the Key Resolve joint drill to be held in March, the two nations' forces will jointly conduct exercises to remove North Korea's nuclear weapons and WMDs," a military source said, asking not to be identified. "Although this exercise first began in 2009, (the military) will strengthen the program this year."

The move came after the North last November revealed its uranium enrichment facility, adding to international concerns about the communist nation's nuclear capabilities. Uranium, if highly enriched, can be used to make weapons, providing Pyongyang with a second way of building atomic bombs after its existing plutonium-based program.

In support of South Korea-U.S. joint military drills, a group of specialized agents from the 20th support command of Maryland will be deployed to the nation, the source said, without giving the exact number of staff members.

The joint anti-WMD program involved 150 American professionals in 2009 and had 350 last year, the official noted, adding the number is expected to rise this year as well.