South Korea and the United States will start their annual military drills next month, military officials said Thursday, despite North Korea's rejection of family reunions citing the planned exercises.

The computer-based simulation, called Key Resolve, will be held for two weeks in late February to early March to improve the combined forces' operation and combat capabilities to deter threats from the North.

The Combined Forces Command (CFC) said forces of the two nations are currently preparing for the exercise, without elaborating on the details of the schedule and participating forces.

"This exercise is one of two major annual combined exercises on the Korean peninsula. Key Resolve focuses on crisis management and command and the control of alliance forces," the CFC said in a release. "We will exercise and train in accordance with our current alliance arrangements."

Following Key Resolve, a joint field training exercise called Foal Eagle will run through the end of April to test the combat readiness of South Korea and U.S. forces.

The large-scale drills are expected to draw a strong response from the North, which has routinely denounced them as a practice invasion.

On Thursday, Pyongyang rejected Seoul's proposal to hold reunions of families separated after the Korean War, citing recent military drills in South Korea and its separate joint military exercises with the U.S. scheduled in spring.

Although Pyongyang has routinely called the annual training a rehearsal for a northward invasion, its rhetoric turned more hostile last year under young leader Kim Jong-un, even threatening nuclear strikes against the South and the U.S.

In a show of force, the allies brought nuclear-cable bombers, stealth F-22 jets and nuclear attack submarines from overseas U.S.

bases on the peninsula for the drills. 

Seoul's defense ministry said it will hold the joint drills as planned.

"As long as the military exists, training is necessary,"

ministry spokesman Kim Min-seok said. "Key Resolve and Foal Eagle exercises are defensive drills."

South Korean Defense Minister Kim Kwan-jin earlier predicted the high probability of North Korean provocations between late January and early March, apparently mindful of unprovoked attacks in response to the drills.

According to military officials, South Korean and U.S. forces have recently stepped up their vigilance, as the North may launch provocations in protest of the allies' joint drills.

About 28,500 U.S. troops are stationed in South Korea, a legacy of the Korean War that ended in an armistice rather than a peace treaty. (Yonhap News)