The combined forces of South Korea and the US "actually" began their joint annual military exercises on Monday amid North Korea's harsh criticism against it, according to local media reports.

The two allies "actually" launched the computer-simulated command post exercise (CPX), scheduled to last for about half a month, local broadcaster YTN reported.

During the next 10 days following the CPX, the combined forces would intensively verify the South Korean military's initial operational capability (IOC) for the transfer of wartime operational control of the South Korean troops from Washington to Seoul.

South Korea's wartime operational command was handed over to the US-led UN Command after the three-year Korean War broke out in 1950. Seoul regained its peacetime command in 1994.

The South Korea-US military drills came amid North Korea's denunciation. After test-firing two short-range projectiles on July 25, Pyongyang sent warnings against the planned South Korea-US drills and Seoul's adoption of the US-made stealth fighter jets.

Since then, Pyongyang fired off four more short-range projectiles in just over a week.

An unnamed South Korean military official was quoted by Yonhap news agency as saying that the drills, which began on Monday, would not be officially called the South Korea-US joint military exercises, noting that the announcement on the joint military drills would be made later this week.

South Korea and the US scrapped or scaled down their joint annual war games, codenamed Key Resolve, Foal Eagle and Ulchi Freedom Guardian, since the first summit between South Korean President Moon Jae-in and North Korea leader Kim Jong-un last year and the first-ever North Korea-US summit in June of the year.

In March this year, the combined forces staged the new Dong Maeng exercise to replace the Key Resolve command post exercises and the Foal Eagle field training drills.