In the letter, Seoul explained the result of its investigation into the land mine detonation in the Demilitarized Zone, calling the UNSC’s attention to the provocation, which it calls a “threat to peace on the Korean Peninsula and a violation of the Armistice Agreement.”

“Upon our request, the letter has been read by the member states of the UNSC. The letter is expected to be adopted as an official UNSC document today or tomorrow, and posted on the UNSC-related website as well,” the official told reporters.

The latest provocation has sharply raised cross-border tensions, leading the two Koreas to begin intensive propaganda campaigns against each other through loudspeakers near the heavily fortified border.

Seoul’s investigators concluded that the North placed three wooden-box land mines intentionally near the Military Demarcation Line within the DMZ separating the two Koreas. Seoul warned that Pyongyang would “pay dearly” for the incident, while the North denies its responsibility.

The letter is not specifically intended to urge the UNSC to issue a statement against the provocation. But it would be part of an accumulation of evidence of Pyongyang’s continued provocations that threaten the peninsular peace and stability, the official noted.

“We sent the letter, believing that, should the North engage in another provocative act, this letter would show to the international community the repetitive nature of North Korean provocations,” he said. “As the act of sending the letter is quite rare, this shows that we took the case very seriously.”

Meanwhile, 38 North, run by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies, said that recent satellite imagery indicates that Pyongyang has conducted an engine test at a satellite launch station on its west coast.

This analysis came amid growing speculation that the reclusive state might engage in a provocative act around Oct. 10, the 70th anniversary of the foundation of its ruling Workers’ Party.

The research website also said that the North has been installing two new, larger, storage buildings for fuel and oxidizer at the rocket launch site. But it pointed out that recent satellite imagery still shows “no signs of launch preparations.”

“When complete, they will provide more than double the storage capacity of the existing structures, suggesting that the North Koreans are developing a capability to test larger, more capable engines,” the website said.

Local media reports said that the North was spotted preparing for short-range missile launches at its launch sites on its east and west coasts. The missiles could be KN-02 ground-to-ground missiles with ranges of up to 160 km or Scud missiles with ranges of up to 1,000 km.

The North has launched short-range missiles in a show of force before or after the South Korea-U.S. military drills, which it has denounced as a “rehearsal for a nuclear war of invasion” against it.

By Song Sang-ho (sshluck@heraldcorp.com)