South Korea demands North Korea explanation for deadly flood

South Korea today pressed North Korea to explain a deadly surge in a river flowing across the border from the North that killed three South Koreans and left three others missing.

The level of the Imjin River suddenly doubled Sunday, sweeping away six people camping and fishing near the border dividing the two Koreas. South Korean officials suspect the estimated 40 million tons of water came from a new North Korean dam — one that some in the South had warned the North could use as a weapon.

The South Korean government demanded an explanation in a message sent to North Korea today, Unification Ministry spokesman Chun Hae-sung said.

"We demand that North Korea provide advance notice if it plans to discharge waters in the future," he said.

South Korean and U.S. officials were investigating why the North might funnel such a large amount of water to the South, but there were no immediate signs the move was meant as an attack, Defense Ministry spokesman Won Tae-jae told reporters.

Later today, Prime Minister Han Seung-soo inspected rescue operations at the site and said his government "is strongly urging" North Korea not to repeat similar incidents in the future, according to his office.

There were concerns the flooding incident, if deliberate, might indicate another turn in the recently thawing relations between the two Koreas.

North Korea and South Korea technically remain in a state of war, divided by a heavily militarized border, because their three-year conflict in the 1950s ended in a truce, not a peace treaty.

Relations blossomed under the "Sunshine Policy" espoused by two liberal South Korean administrations but went cold after the election of conservative President Lee Myung-bak 18 months ago.

Pyongyang recently reached out to Seoul again, and the two Koreas agreed to restart joint economic projects and resume the reunions of families divided during the Korean War.

Despite the overtures, "this is not something that we can overlook," the JoongAng Ilbo newspaper said in an editorial Monday. It warned that South Korea would suffer "unimaginable damage" if the North uses the dam for military purposes.

On Sunday morning, the river's water level jumped from 7.5 feet (2.3 meters) to 15.1 feet (4.6 meters), local Gyeonggi Province official Choi Kwon-rak said. He said there was no natural cause for flooding since it had not rained in the area for several days.

Rescuers found three bodies early Monday and were searching for three others, local fire official Hwang Tae-geun said. Some 2,500 rescuers and army soldiers were mobilized Monday, he said. The area is less than 6 miles (10 kilometers) from the Korean border.

There was no mention of the incident in North Korea's official Korean Central News Agency. The Unification Ministry said the North also hasn't responded to the South Korean message more than six hours after it was sent.

South Korean officials have raised concerns that the Hwanggang Dam could cause water shortages or flooding in the South, with some concerned the dam could be used as a weapon. Unification Ministry officials said South Korea conveyed such concerns to North Korea during talks in 2006 and 2007, but the North hasn't responded.

As part of anti-flooding efforts, South Korea has been building two dams in the area, scheduled to be completed by 2011 and 2012, respectively. On Monday, the Ministry of Land, Transport and Maritime Affairs said in a statement it will advance the construction of the first dam by one year in the wake of Sunday's flooding.

The ministry said the North Korean dam is located about 26 miles (42 kilometers) north of the border, and intended to channel water to a hydroelectric plant and for crop irrigation. It is estimated to have a capacity of 400 million tons of water.