North Korea has threatened to cancel family reunions with the South, a day after agreeing to hold them.
Its top military body said in a statement that it would reconsider the deal if joint US-South Korea military exercises went ahead.
"Dialogue and exercises of war" could not go hand in hand, South Korea's Yonhap news agency quoted the North Korean statement as saying.
The two Koreas last held reunions for divided families in 2010.
The next reunions—for family members separated when the Korean peninsula was partitioned at the end of the 1950-53 Korean War—are scheduled for 20 February.