SEOUL » The rival Koreas sat down Friday for a 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 recently pushed for better ties with Seoul and 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.

But the country is still sending a mixed signal. It has threatened to hold off the family reunions set for Feb. 20-25 in protest of the South Korea-U.S. military drills scheduled to start later this month. And a U.S. research institute said Thursday that North Korea has accelerated work at a site used for three previous underground nuclear test explosions, though a test doesn’t appear imminent.

Senior officials from the Koreas met at the border village of Panmunjom on Wednesday in their highest-level talks in years, but the meeting ended with little progress. A key sticking point was North Korea’s demand that South Korea postpone the start of its annual springtime war games with the U.S. until the reunions end, according to South Korean officials. South Korea has made it clear it would go ahead with the drills.

North Korea calls the exercises a rehearsal for invasion, while South Korea and the U.S. say they are defensive in nature.

The spat quickly spawned worries that North Korea may cancel parts of the family reunions because they overlap with the first two days of the military drills. But in an indication that North Korea doesn’t want a deadlock in relations to impact its hopes of restarting lucrative jointly run cooperation projects, it proposed holding a second round of senior-level talks.

On Friday morning, delegations from the Koreas met at the same border village, 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 track 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.