SEOUL, Nov 13 (Reuters) - South Korea's military said it will hold a three-day joint exercise with the United States and Japan starting on Wednesday, featuring fighter jets and marine patrol aircraft as well as the U.S. nuclear-powered aircraft carrier USS George Washington.

The "Freedom Edge" exercise is a response to what the South Korean military said were threats from North Korea, which recently conducted an intercontinental ballistic missile test, drawing condemnation from Seoul, Tokyo and Washington.

It also comes as the U.S. State Department said North Korean troops have started engaging in combat operations in Russia's war with Ukraine.

The exercise will include South Korean and Japanese fighter jets and maritime patrol aircraft, as well as the USS George Washington, Seoul's Joint Chiefs of Staff (JCS) said in a statement.

The trilateral exercise follows a first round held earlier this year after the leaders of the three countries agreed at a summit in 2023 to hold annual training drills.

Pyongyang has long condemned joint drills between South Korea and the United States, calling them a rehearsal for invasion.

The trilateral exercise will also include maritime missile defence training and cyber defence training, according to the JCS.

In a statement on Tuesday, the U.S. Air Force said it would retire its A-10 Thunderbolt II aircraft in key regions including South Korea in the fiscal year 2025 as part of its modernisation strategy.

The aircraft, nicknamed "The Warthog", was developed for the U.S. Air Force by the Fairchild Republic Company, which is now part of Northrop Grumman (NOC.N), opens new tab, according to the U.S. defence company's website.