SEOUL -- Combined forces of the Republic of Korea (ROK) and the United States on Sunday launched the planned joint springtime war game, local media reports said.

Citing Seoul's defense ministry, local media reported that the Foal Eagle field training exercise started early Sunday as announced. It would last for about four weeks, while the Key Resolve computer-simulated command post exercise would continue for two weeks from mid-April.

The defense ministries of the two countries announced plans on March 20 that they had agreed to resume the delayed annual war games from April 1 in a similar scale to the one last year.

The joint military exercises were postponed to make the ROK-hosted Winter Olympic and Paralympic Games a peace Olympic.

In 2017, the Key Resolve and the Foal Eagle had continued for about two months from March 1, mobilizing strategic US military assets such as nuclear-powered aircraft carrier, nuclear-capable submarine, strategic bomber and stealth fighter jets.

For this year's military drills, the combined forces allegedly planned to minimize the US strategic asset mobilization. Even if the strategic military assets are deployed to the Korean Peninsula, it would not be made public.

The number of US soldiers to be mobilized to the joint drills would be similar with last year, with 12,200 US troops participating in the Key Resolve and 11,500 US soldiers in the Foal Eagle. About 290,000 ROK forces will be mobilized to the military exercises.

Meanwhile, peace activists demanded the two countries stop conducting the joint war games.

The People's Solidarity for Participatory Democracy (PSPD) said in a statement that the war games were still massive in scale and aggressive in nature though they were scaled down this year, noting that the military drills were carried out under the scenario of military conflicts requiring a US reinforcement to the peninsula.

It would be a basic action, the statement said, to stop all military actions targeting each other while dialogue lasts. It urged the two allies to consider stopping the scheduled joint war game in the second half of this year for peace on the peninsula.