North Korea and Russia have reportedly launched talks to redefine their boundaries.

Russia’s Foreign Ministry said Thursday that Moscow and Pyongyang agreed late last year to hold a working-level discussion aimed at producing a new treaty to adjust the charting of their border.

The talks come eight years after they held a similar border discussion in Pyongyang in which they defined the border as the area around the estuary plain of the Tumen River.

The estuary of the river gets submerged during the summer rainy season and reveals itself during the dry winter season resulting in geographical shifts that make it difficult for the two nations to define a clear boundary.