South Korea and the United States will carry out their annual joint military drills in a "low-key" manner from this week, the military said Sunday, amid the ongoing reunions of families separated by the 1950-53 Korean War.

The allies will hold the computer-based command post exercise, called Key Resolve, from Monday to March 6, involving about 10,000 South Korean and 5,200 American forces, with 1,100 coming from overseas U.S. bases. 

The two allies also plan to hold a combined field training drill, called Foal Eagle, which involves a set of ground, air, naval, expeditionary and special operations from Monday to April 18. The field training involves 7,500 American troops, with 5,100 of them coming from abroad.

The joint military drills come as the Koreas are holding a series of family reunions at Mount Kumgang, a scenic resort on the North's east coast.

On Saturday, 82 elderly South Koreans, accompanied by 58 family members, returned from the North's mountain resort after spending three days with their long-separated loved ones, with 357 South Koreans set to reunite with 88 relatives from the North later Sunday.

Citing the South Korea-U.S. military drills, Pyongyang had threatened to boycott the family reunions, but later backed down and agreed to hold the reunions as planned.

North Korea has called the military exercises "a rehearsal for invasion of the communist country," but Seoul and Washington maintain that their military maneuvers are defensive in nature.

With family reunions under way, military officials said, the allies will stage a "relatively low-key" exercise without involving high-profile nuclear bombers and carriers so as not to provoke the North. 

Last year, some 220,000 South Korean troops participated in the joint military drills, and the U.S. mobilized a nuclear-powered aircraft carrier, F-22 stealth fighters and B-52 nuclear bombers to the peninsula, which drew an angry response from the communist state and sharply stoked regional tension.

On Sunday, North Korea denounced the U.S. for hurting the mood for improving ties between the Koreas by pushing ahead with the joint military exercises.

"The U.S. is pressing ahead with the Key Resolve and Foal Eagle exercises that are heightening tensions on the Korean Peninsula," the North's state-run Rodong Sinmun newspaper quoted a Pyongyang official as telling a United Nations meeting. "It shows that Washington is the main culprit for dividing the Korean people and bringing the threat of nuclear war to the peninsula."

About 28,500 U.S. troops are stationed in South Korea to help deter North Korean aggression. South and North Korea remain technically in a state of war as the Korean War ended in a ceasefire, not a peace treaty. (Yonhap)