The United States will send a larger number of troops to this year's major joint military exercises with South Korea than last year's, Seoul's defense ministry said Monday.

The allies plan to stage their annual major drills -- Key Resolve, a computerized command post exercise (CPX), and the field training exercise (FTX) Foal Eagle -- starting in early March to check and boost their crisis management abilities and joint readiness posture.

"As for the Key Resolve and Foal Eagle exercises, the total number of the U.S. service members will be slightly larger than the previous year," defense ministry spokesman Kim Min-seok said in a regular press briefing, refusing to provide exact figures.

"Fewer soldiers will take part in the Foal Eagle drill, while more will be mobilized for Key Resolve," he said, noting that the expected changes mean that this year's drills put more focus on the simulation-based war game.

Last year, the two-week drill Key Resolve starting in February involved 10,000 South Korean troops and some 5,200 American forces.

For Foal Eagle, some 200,000 South Korean forces and 7,500 American troops were mobilized.

"The bigger emphasis on the CPX indicates that the allies need more time to analyze and review diverse scenarios for North Korea's provocations as the communist country has come up with evolving tactics, including hacking attacks," a military officer in Seoul said on condition of anonymity.

"The reduced number of soldiers for the FTX appears to have something to do with the U.S. defense budget constraint," he added.

While refusing to provide data on the scheduled exercises, the U.S. Forces Korea simply said, "More information on the exercise will be available at a later date."

The planned drills are expected to further heighten tensions on the Korean Peninsula, as North Korea has repeated threats, claiming the exercises are "a dress rehearsal for a northward invasion."

Seoul and Washington said the regular drills are defensive in nature. (Yonhap)