A North Korean propaganda media outlet warned South Korea on Sunday of an "unpredictable situation" if Seoul lights up a giant Christmas tree-shaped tower near their tense border.

It had been an annual tradition for South Korea to light up the Christmas tree on top of a hill called Aegibong near the western border with the North before it was suspended in 2003 under a reconciliation agreement with the North to end border propaganda activity.

But the South resumed lighting the 30-meter-tall tower last year after the North's deadly artillery attack on a border island in the Yellow Sea. Pyongyang has strongly condemned the move with a series of warnings that it will strike down the glowing structure that it denounces as psychological warfare.

On Sunday, the North Korean Web site Uriminjokkiri denounced Seoul's plan to light up the tower this year, saying the move is aimed at provoking the North and stepping up anti-North Korea psychological warfare. It also warned that the South will bear the "entire responsibilities" if an "unpredictable situation" happens.

The glowing structure has served as a symbol of the prosperous South in contrast to the destitute North, which is apparently concerned that the lights would weaken its regime's ideological control of its hunger-stricken people.

The Aegibong peak is just across a border river that separates the two Koreas. A glowing Christmas tree at the peak can be seen with the naked eye from as far as the major North Korean border city of Kaesong. (Yonhap News)