North Korean chief delegate Won Tong Yon, center, walks with other delegates after crossing a military demarcation line, which has separated the two Koreas since the Korean War, for a meeting with South Korean delegates at the border village of Panmunjom on Feb. 12, 2014. South Korean Unification Ministry/AP

The two Koreas sat down Friday for their second round of talks this week at a border village as the North's calls for a delay of annual South Korea-U.S. military drills threaten plans for the resumption of emotional reunions of war-divided families.

A year after dramatically raising tension with repeated threats of nuclear wars and vows to bolster nuclear capability, North Korea has been pushing for better ties with Seoul. It agreed to arrange reunions of families separated by the 1950-53 Korean War for the first time in more than three years. Analysts say the impoverished North needs good relations with Seoul to win outside investment and aid.

North and South Korea met at the border village of Panmunjom on Wednesday in their highest-level talks in years, but the meeting ended with little progress.

On Friday morning, delegations from the Koreas met again, South Korean Unification Ministry spokesman Kim Eui-do told reporters.

Details of the closed-door meeting weren't immediately available. Kim said South Korea was firm in its opposition to linking the military drills to the family reunions.

South Korea has dismissed North Korea's proposal for a series of measures that the North says are needed to ease tensions, saying Pyongyang must first take steps toward nuclear disarmament and show how sincere it is about improving ties.

On Wednesday, North Korea refused to discuss nuclear issues, according to the Unification Ministry.

North Korea has a record of launching surprise provocations and scraping cooperation projects with South Korea when it fails to win outside concessions. It canceled family reunions at the last minute in September when it accused Seoul of preparing war drills and other hostile acts.

On Thursday, U.S. Secretary of State John Kerry and his South Korean counterpart Yun Byung-se warned North Korea against any possible aggression, saying the North should not use the military exercises as an excuse to stay away from talks or to delay attempts to improve ties.

The Associated Press