North Korea released water from a border dam into a river flowing to South Korea, prompting officials in the South to evacuate campers along the river, but no damage or casualties were reported, officials said Saturday.

The North began discharging water from its Hwanggang Dam into the Imjin River on Friday. Water levels of the river began rising sharply at around 2:20 a.m. to as high as 5.24 meters at 8:20 a.m. Saturday before beginning to fall, officials said.

It usually takes about eight to nine hours for discharged water to reach the Pilseung Bridge, a water level measurement point in the cross-border river in the South.

Dozens of campers along the river have been evacuated, officials said.

Officials said they believe the North opened the dam as rain raised dam water levels.

An official at the unification ministry in Seoul, which handles relations with the North, said the North did not give prior notice before the latest release.

In September 2009, North Korea abruptly released water from the dam near the western part of the inter-Korean border without notifying South Korea, causing a flash flood that killed six people. (Yonhap)