WASHINGTON, March 1 (Xinhua) -- The United States and South Korea would downgrade two large-scale joint military exercises this spring, U.S. media reported on Friday.

The two major exercises, known as Key Resolve and Foal Eagle, would be replaced with a limited version of "mission-specific training," NBC News reported, citing two U.S. defense officials.

The downgrade decision came right after the conclusion of the Hanoi summit between President Donald Trump and Kim Jong Un, top leader of the Democratic People's Republic of Korea (DPRK), which failed to reach an agreement.

U.S. officials said that the downgrade decision has been under consideration for some time and was not related to the Hanoi summit, according to the report, adding that the decision was expected to be announced by the United States and South Korea in the next few days.

Following his first summit with Kim in Singapore last June, Trump announced that Washington would suspend large-scale joint military exercises with Seoul, underlining the vast cost of the exercises.

The combined forces of the United States and South Korea have annually staged springtime war games from March to April, including the Key Resolve command post exercise and the Foal Eagle field training drill.

The DPRK has denounced the war games as a dress rehearsal for northward invasion.

About 28,500 U.S. troops are stationed in South Korea, vestigial of the 1950-53 Korean War which ended with an armistice.