North Korea appears to have released water from a dam near the inter-Korean border without prior notice to South Korea, raising water levels in the Imjin River, which flows across the border.

The Ministry of Climate, Energy and Environment said Sunday that an analysis of satellite images taken around 11 p.m. Saturday indicated that North Korea discharged water from the Hwanggang Dam, located on the Imjin River upstream from northern Gyeonggi Province.

As of 10:20 a.m. Sunday, the water level under Pilseung Bridge, downstream from the dam on the South Korean side, stood at one-point-84 meters.

The water level reached about one meter early Sunday, but has risen rapidly and continues to climb slowly.

The ministry explained that rain has continued along the North Korean section of the Imjin River since Friday, and with more rain expected starting Monday, North Korea appears to have begun releasing water.