Radio Free Asia reported Saturday that satellite imagery suggests North Korea released water from its Hwanggang Dam, which could potentially inflict damage on border areas in South Korea.

The report said that satellite photos taken on Thursday and Friday by Planet Labs show white foam likely caused by a discharge from the dam for two days in a row.

Hwanggang Dam. located on the upper Imjin River. has a storage capacity of some 350 million tons. and a water release can cause major flooding on the South Korean side.

In 2009, an unannounced release by the North claimed six lives in the South, after which the two Koreas agreed on a notification rule but the last such prior notice the North made was in July 2013.

Radio Free Asia also cited satellite images of Kim Il Sung Square and Mirim air base in Pyongyang taken Thursday, showing red objects, vehicles and troops, possibly indicating preparations for a military parade, which the regime said it will hold to mark its foundation day on September 9.