American and South Korean forces began their annual joint training operation, Foal Eagle, last week – amid increased tensions with North Korea.

North Korea has tested ballistic missiles that are believed to be nuclear capable twice over the past month, including a volley of four missile launches into the Sea of Japan over this past weekend.  Concerns about North Korea’s developing nuclear capability have prompted the United States to install THAAD anti-missile defense systems in the region – a move which has elicited angry responses from North Korea and another trouble-maker in that corner of the world, China.

Foal Eagle is an annual joint forces operation, in which the United States assists South Korea is assessing their ability to counter an invasion force from their northern neighbors.  Much of South Korea’s military training is centered around the North Korean threat, as war between the two states was never formally called off after the Korean War decades ago.

The exercises include a series of operations that call on combined ground, air, naval and special operations units to work together to accomplish objectives similar to those they might face in open war against a North Korean adversary, but despite the lens of these operations being focused squarely on one nation, officials from both the American and South Korean military have emphasized that this operation, like Foal Eagle training exercises before it, is strictly a defensive exercise.

“These exercises are defensive in nature, and they have been carried out regularly, openly and transparently for nearly 40 years,” Pentagon spokesman, Navy Captain Jeff Davis, told reporters.

About 3,600 additional U.S. service members have been deployed to South Korea in support of the exercise.  There, they’re joined by the 28,000 American troops currently stationed in the country, and South Korea’s active duty military, where a series of operations will be conducted through April 1st, in which the intent is to “increase readiness to defend South Korea, to protect the region, and to maintain stability on the Korean Peninsula.”  Last year, as many as 300,000 South Korean military personnel participated in the training efforts.

American Secretary of Defense, James Mattis, visited South Korea recently, in which he reaffirmed America’s commitment to the defense of the Asian nation and kept the ball rolling with ongoing plans to place a THAAD missile defense system in the nation.

“It remains our intent to have [THAAD] there and in an operational state as soon as feasible,” Davis said. “This is a critical measure that we’re taking to defend the Korean people and alliance forces against North Korean missile threats, a very serious threat as highlighted by the Feb. 12 ballistic missile launch by North Korea.”