The United States and South Korea have signed a new agreement aimed at deterring the possible use of nuclear arms and other weapons of mass destruction by North Korea.
The strategic plan was signed on October 2 during a visit to Seoul by U.S. Defense Secretary Chuck Hagel.
No specifics about the pact were released.
But Hagel said the United States is committed to using all its military capabilities to provide its ally with what he described as "extended deterrence" against the North.
Hagel and South Korean defense chief Lim Kwan-jin also discussed a South Korean request that U.S. forces continue to be in command of U.S. and South Korean troops in the event of a war with North Korea.
South Korea is scheduled to take over the wartime command in 2015.
Based on reporting by Reuters and AFP