US Marine Corps amphibious assault vehicles land on the seaside during a joint landing operation drill in the city of Pohang to the southeast of Seoul on March 29, 2012.
South Korea and the United States have started a massive joint naval drill in the Yellow Sea amid high tensions on the Korean peninsula.
The three-day-long exercise kicked off on Saturday, involving at least 10 South Korean warships and submarines plus the US nuclear-powered aircraft carrier, the USS George Washington, the South Korean Defense Ministry announced on Saturday.
"The naval exercise started as scheduled today," a Defense Ministry spokesman said.
Some 8,000 personnel from the two allies' forces participated in the maneuver, the ministry noted.
The drill is aimed at joint detection and tracking down of long-range missiles launched by North Korea as well as interception of its submarines.
The maneuver came as a follow-up to a two-day-long trilateral naval drill among South Korea, Japan, and the US off the southern South Korea island of Jeju, involving destroyers, supply ships, and helicopters.
The troops involved in the two-day-long exercise practiced humanitarian operations such as search and rescue missions over Thursday and Friday.
Pyongyang, however, criticized the three-nation exercise, describing it as "an intentional act to provoke war,” saying it would bring a "new cloud of war" to the volatile region.
However, Seoul says the drills are routine and defensive in nature.
The US and South Korea have conducted numerous massive joint naval and aerial drills in the waters east of the Korean Peninsula.