South and North Korea ended their high-level talks meant to break an impasse in their relations, Seoul's unification ministry said Friday.

The ministry, which handles inter-Korean affairs, did not say whether the rival Koreas reached a deal on family reunions and the upcoming joint South Korea-U.S. military exercises.

The rival Koreas have locked horns over the military exercises that partly overlap with a new round of reunions of separated families set to be held at a North Korean mountain resort from Feb. 20 to 25.

On Wednesday, the North demanded that Seoul reschedule the military exercises until after the family reunions end, a request spurned by Seoul.

The dispute over the military exercises has cast doubt on the planned reunions. South Korea plans to send a 15-member advance team to the North on Saturday to prepare for the reunions, said ministry spokesman Kim Eui-do. 

The communist country has reacted sensitively to South Korea-U.S. joint military exercises for decades, condemning them as a rehearsal for invasion.

Seoul and Washington say the annual exercises are defensive in nature and have nothing to do with the reunions of families separated by the 1950-53 Korean War.

"We will make sure that the family reunions won't be hindered because of the military exercises and there won't be any disruptions to the exercises because of the reunions," presidential spokesman Min Kyung-wook said Friday, citing an unidentified government official.

On Thursday, U.S. Secretary of State John Kerry said there is no legitimate excuse for linking the military exercises with the reunions.

"The United States does not believe that it is appropriate to link a humanitarian issue such as (family) reunification with any other issue," Kerry said in a joint press conference with his South Korean counterpart in Seoul.

Millions of Koreans remain separated since the Korean War ended in a cease-fire, not a peace treaty.

Family reunions are a pressing humanitarian issue on the divided peninsula, as most of the separated family members are in their 70s and 80s, and wish to see their long-lost relatives before they die. (Yonhap)