The Army needs to slow down its troop reduction and maintain a troop level of at least 420,000 through 2030 in the face of North Korea's 1.02-million-strong army, two military experts claimed Tuesday.

Under the Army's troop-cut plan, which has been in the offing for years to streamline and modernize its forces, the number of its troops will be reduced to about 500,000 in phases by 2020 and 387,000 by 2030, from the current level of 650,000.

The plan has drawn concern since North Korea's two military attacks in 2010 -- the sinking of the Cheonan warship and the shelling of Yeonpyeong Island -- killed 50 South Koreans, mostly soldiers.

"The large-scale reduction of ground troops, which could cause catastrophic consequences in the future, should be implemented after verification," the experts said in a joint report presented at a security forum hosted by the Army.

The experts are Kwon Hyeok-chul, a professor at Korea National Defense University and Lee Chun-keun, a senior researcher at the Korea Economic Research Institute.

The Army's troop-cut plan was set years before the U.S. decided to reduce its defense spending, a move that could weaken Washington's defense posture on the Korean Peninsula, so South Korea's military needs to revise it, they said.

Officials in Seoul said South Korea and the U.S. have started discussions to readjust their military strategies on the Korean Peninsula.

The discussions included an idea of transforming a front-line American military unit near the border with North Korea into joint forces of the two allies to better deter the communist nation.

The proposed transformation, if realized, would likely mean that the 2nd Infantry Division won't move away from the border with the North under a force realignment plan, and continue to play a "tripwire" role deterring North Korean aggression, officials said.

The forward-deployed division, which has been considered a symbol of the Korea-U.S. military alliance, is currently scheduled to move to Pyeongtaek, 70 kilometers south of Seoul, once South Korea takes over wartime operational control of its troops in December 2015.

As a legacy of the 1950-53 Korean War, the wartime operations of South Korean troops remain under the control of the top U.S. military commander in the country. Some 28,500 U.S. troops are stationed in South Korea.

South Korea's military has vowed a tougher retaliation if North Korea stages an armed attack again.

The two Koreas remain technically at war because the Korean War ended in a cease-fire, not a peace treaty. (Yonhap)