“Our high-speed patrol boat repelled the North Korean patrol boat,” the South Korean Office of the Joint Chiefs of Staff said in a statement. “We are fully prepared for further provocations from the North Korean military.”
There was no immediate report of the incident by the official North Korean news agency.
The skirmish comes just days before President Barack Obama is due to begin a weeklong visit to Asia. North Korea’s nuclear weapons program will be a key topic when Mr. Obama stops in Seoul next week to meet with President Lee Myung-bak.
One North Korean warship was partially destroyed in the fighting on Tuesday, according to a report by the Yonhap news agency, and the vessel managed to retreat to the North. The military said there were no casualties on the South Korean side.
The Yonhap account, citing an unidentified government source in Seoul, said fighting erupted when a North Korean navy boat ventured across the so-called Northern Limit Line, a sea border drawn by the United Nations at the end of the 1950-53 Korean War. The demarcation line has never been accepted by North Korea.
The South Koreans first issued warning broadcasts, then fired warning shots when the broadcasts were ignored.
“It was then that the North Korean patrol boat attacked our high-speed patrol boat,” the military’s statement said. “Our ship returned the fire.”
It was unclear how many warships were engaged in the fighting. Nine South Korean fishing boats had been in the area but were safely evacuated, Yonhap said.
The fighting took place near Daecheong-do, a South Korean-held island about 125 miles west of Seoul. The island is located just 18 miles off the North Korea coast.
The disputed waters remain the most volatile section of the Korean border, with North Korea regularly warning that a skirmish there could trigger a full-blown war. It claims a maritime borderline far below the North Limit Line.
There have been a number of accusations of North Korean naval intrusions over the past decade. In one recent incident, in June, the South charged that a North Korean patrol boat had breached the line..
The two navies engaged in bloody skirmishes in the disputed area in 1999 and 2002.
In the 1999 incident, two North Korean warships were sunk with an unknown number of casualties, and seven South Korean sailors were injured. In the fighting in 2002, one South Korean patrol boat was sunk and six South Korean sailors were killed.
Afterward, South Korea beefed up its forces in the disputed waters.
The Korean peninsula is still technically at war; fighting ended in 1953 with a truce, not a formal treaty. The uneasiness of the peace is best symbolized by the naval skirmishes in the western waters and the North’s territorial claim there.
After a long-range rocket launching in April and a second nuclear test in May, North Korea has recently begun reaching out to both Seoul and Washington. In September, for example, it allowed a new round of temporary reunions of Korean relatives who were separated by the war. The South responded by offering 10,000 tons of corn in humanitarian aid.
Washington has indicated that it would start bilateral talks with Pyongyang to persuade it to return to six-nation talks about ending its nuclear weapons program.