The water level at the North Korean dam had been detected to have risen to full capacity with the area having massive rainfalls in recent weeks.

Six South Koreans were killed in September 2009 after North Korea released a massive amount of water from the border dam without prior warning.

Shortly after the incident, North Korea agreed with the South to notify each other in advance before any dam water discharge.

The North Korean dam is located about 42 kilometers north of the inter-Korean military demarcation line and its full capability is believed to be about 300 million to 400 million tons.

As the discharged water will flow downstream through the Imjin River to the South, Seoul aired warning broadcasts and sent text messages in the border neighborhoods, urging fishermen and residents to stay clear of the river.

Seoul's unification ministry, meanwhile, urged North Korea to honor an inter-Korean agreement over dam water discharge. It also made clear that such signs of good faith must precede any meaningful bilateral talks.

"If North Korea has a genuine interest in improving inter-Korean ties and holding dialogue with the South, it should first show its willingness to cooperate with Seoul starting with such areas as dam water discharge," Jeong Joon-hee, ministry spokesman, said in a regular press briefing. (Yonhap)