Marine Corps officials from South Korea and the United States on Wednesday called on troops to stay vigilant against  threats of North Korea's weapons of mass destruction.

South Korean Marine Corps Commander Lt. Gen. Lee Sang-hoon and Lt. Gen. Lawrence D. Nicholson, commanding general of the III Marine Expeditionary Force, visited the 6th brigade on Baengnyeong Island near the western maritime border with North Korea, to check military readiness against the North and discuss countermeasures, the Marine Corps said in a statement.
 

They vowed to strongly retaliate against North Korea if provoked.

It marked their second on-site inspection following their visit to Yeonpyeong Island in August last year.

The North's shelling of Yeonpyeong left four South Koreans dead in November 2010. The shelling followed a torpedo attack in March on a South Korean warship that killed 46 sailors.

There is no unusual military movement in the North, with the annual Foal Eagle and Key Resolve exercises underway in the South, according to the defense ministry.

Seoul and Washington kicked off their annual joint drills -- Key Resolve and Foal Eagle -- in March. The two-week Key Resolve started Monday, while Foal Eagle runs through the end of April.

Pyongyang has long denounced the exercises as rehearsals for an invasion despite Washington's assurance that they are defensive in nature. (Yonhap)