North Korean leader Kim Jong-un's proposal to hold military talks with South Korea should be considered seriously as it offers a chance to keep tensions under control ahead of August's U.S.-South Korea military exercises, a U.S. expert said Tuesday.

The North's leader made the dialogue offer during the Workers' Party Congress over the weekend, saying the two sides could use such talks to discuss ways to remove risks of clashes along the border and ease tensions as well as other issues of mutual concern.

South Korea immediately rejected the proposal as insincere, saying it makes no sense for the North to propose talks to ease tensions while forging ahead with its nuclear and missile programs.

It urged Pyongyang to first halt provocations and return to the stalled nuclear talks.

But Robert Carlin, a visiting fellow at Stanford University's Center for International Security and Cooperation, said the North's proposal could be "Kim Jong-un himself opening this door to the South Koreans" and should be probed carefully.

"This offer is important because there is only a small window between now and when the August joint exercises start. When those start and if nothing good is going on, tensions are going to go back up again and chances of something bad happening are going to increase," he said during a discussion organized by the website 38 North.

By suggesting military-to-military talks to deal with problems around the Military Demarcation Line (MDL), the North could be "implicitly signalling that they understand that the South Koreans have a role to play in the replacement of the armistice," Carlin said.

"You have to probe that, but it gives this arena of North-South military talks a special and introductory place that could be built into something else. Anyway, unless it's probed, obviously we never know what it means. But it's not unimportant," he said.

Tensions on the divided peninsula usually rise during such military exercises as the communist nation strongly bristles at the maneuvers, calling them a rehearsal for invasion. The South and the U.S. say they are routine defensive exercises.

"If something isn't done during this period of opportunity, then we're going to be facing same sorts of tensions," Carlin said.

"We're going to want to do a robust exercise and they're going to do a robust response to it and then we're going to completely lose the opportunity because we're in the middle of the presidential campaign in the U.S." (Yonhap)