International military authorities are investigating a brief exchange of gunfire fired across the tense border dividing North and South Korea. VOA's Kurt Achin reports from Seoul.

South Korean Army soldiers patrol along barbed-wire fence in Paju, north of Seoul, near demilitarized zone (file photo)

The South Korean Defense Ministry confirmed the exchange, but said there were no casualties.

David Oten, spokesman for the United States Forces in Korea, also says he has no reports of injuries. He says an on-the-spot investigation will be carried out by members of the United Nations Military Armistice Commission, which monitors the DMZ.

"It involves moving to the location and physically looking at the ground, and interviewing the personnel involved," he explained.

South Korean military authorities say the North initiated Monday's incident, about 165 kilometers northeast of Seoul, by firing several machine gun bursts in the direction of the South. The authorities said South Korean forces returned a small number of shots, and issued a verbal warning over a loudspeaker.

North Korea invaded the South in 1950 to start the Korean War. The conflict was halted by a 1953 armistice, but never formally concluded, and the two are technically still at war even though relations have improved in recent years.

The United States deploys about 28,000 personnel here in South Korea to deter a second invasion, and Washington commands the United Nations force that ensures the armistice is observed.

Similar exchanges of fire across the tense border have occasionally occurred in the past. However, Monday's incident is the first since July of last year.

Mechanisms for preventing North-South flashpoints have greatly improved since the two countries held a historic summit in 2000. That meeting paved the way for a series of high-level military talks between the two Koreas. However, the latest round of those military talks broke down last month, in disagreement over the two countries' maritime border.