Floodgates of a North Korean dam near the border with South Korea remain partially open amid heavy rains, the Joint Chiefs of Staff (JCS) said Tuesday, amid concerns the release of dam water could pose threats to South Korean regions downstream.

Whether the North opens the floodgates of Hwanggang Dam has been something to watch for in the South since an abrupt release of dam water in 2009 raised the water levels of the Imjin River downstream and left six campers dead.

The North has since agreed to notify the South in advance of a release but has hardly kept the promise.

"Our assessment is that the floodgates of Hwanggang Dam are partially open due to heavy rains in the North Korean region," JCS spokesperson Col. Kim Jun-rak said during a regular press briefing.

North Korea has recently been hit hard by downpours in many regions, including rice-producing areas in its southern parts. On Monday, state media reported that the North received as much as 200 millimeters of rain in Hwanghae and Kangwon provinces and forecast around 70 mm of rain would fall overnight.

The military is closely monitoring the situation and sharing information with other government agencies to protect the safety of nearby residents and troops, Kim said.

A unification ministry official said the Imjin River is maintaining a stable water level as of Tuesday morning.

"As of 10 a.m. Tuesday morning, the water level at Pilseung Bridge was 6.3 meters. The water levels of the Imjin River are stable," he said. "The water level has gradually decreased after recording 9.2 meters at around 7 p.m. yesterday."

"The government is keeping a close eye on the torrential rainfall situation near the inter-Korean border areas while taking necessary measures for the safety of our people, including evacuating residents beforehand and sharing information with other agencies," the official added.

Last week, the North partially opened the floodgates of Hwanggang Dam on the western inter-Korean border and sent water into the Imjin River, a move that put authorities on alert against a potential rise in water levels in the South.

President Moon Jae-in expressed regret last week over Pyongyang not giving Seoul advance notice. (Yonhap)