North Korea has vowed not to hold upcoming family reunions with South Korea during the period of Seoul-Washington joint military exercises, an official said Thursday, a move that could dim the prospect of the reunions. North Korea agreed last week to stage the reunions at its mountain resort later this month, but it linked them to South Korea-U.S. joint military exercises during their first high-level talks in seven years on Wednesday that ended without any tangible agreement. The North insisted that Seoul delay the military exercises so they won't overlap with the reunions, noting it cannot hold the reunions during the period of the military exercises, the official said. Under last week's deal, South and North Korea are set to stage the reunions at Mount Kumgang, a scenic resort on the North's east coast, from Feb. 20 to 25. South Korea rejected the North's demand to reschedule the military exercises, which are set to run from Feb. 24 through mid-April. The move raised the possibility that the North could stage the reunions from Feb. 20 to 23. "We cannot accept any possible partial reunions," the South Korean official said. North Korea has reacted sensitively to South Korea-U.S. joint military exercises for decades, condemning them as a rehearsal for invasion. Defense Ministry spokesman Kim Min-seok ruled out the possibility of delaying the joint drills. Seoul and Washington say the exercises are defensive in nature. Family reunions are a pressing humanitarian issue on the divided peninsula, as most of the separated family members are in their 70s and80s, and wish to see their long-lost relatives before they die. Millions of Koreans remain separated since the Korean War ended in a cease-fire, not a peace treaty.