South Korea is closely monitoring North Korea in coordination with the United States, the Joint Chiefs of Staff (JCS) said Thursday, after a media report that the North is building a replica of the South's presidential office for a possible assault drill.

On Wednesday, local cable network Channel A reported that the North is building a mini replica of what appears to be the presidential office Cheong Wa Dae or the defense ministry on a desert island near Kilju, North Hamgyong Province.

"We are closely watching (the North's activities) under close South Korea-US coordination," JCS spokesperson Col. Kim Jun-rak said during a regular press briefing, declining to give further details.

In December 2016, North Korea actually conducted a drill to destroy a replica of Cheong Wa Dae under leader Kim Jong-un's guidance.

The report came shortly after President Moon Jae-in expressed hopes that US President Donald Trump and North Korea's Kim meet each other again ahead of the November US presidential election.

A presidential official said Moon's idea has been already conveyed to the White House.

Inter-Korean relations have turned markedly chilly in recent months, with the North blowing up their joint liaison office in its border town of Kaesong in anger over anti-Pyongyang leaflets.

North Korea had threatened to take a series of military actions against the South but has suspended the plan following Kim's order last week. (Yonhap)