South Korea says its navy fired warning shots at a North Korean fishing boat that crossed the maritime border. The incident comes as U.S. and South Korean troops began a 12-day war game.
Officials in Seoul say warning shots were fired after a North Korean fishing boat entered disputed waters along the western sea border on Monday. The South Korean military says the boat turned back after the shots were fired.
There have been two deadly naval clashes between the two sides in the area, one in 1999 and one last year. North Korea does not recognize the maritime border there and has often tried to send boats into the area's rich fishing grounds.
Monday's incident took place as South Korean and U.S. troops began joint maneuvers. The annual exercise, known as Ulchi Focus Lens, involves 14,000 American troops, many of them based in South Korea. The South Korean military has not indicated how many of its troops are participating but says it is the largest such exercise.
Pyongyang has condemned the war game as a practice run for an invasion of North Korea.
Also on Monday, North Korea announced it would not participate in this month's World University Games in the South.
More than 200 athletes and 300 supporters from the communist state had been expected to arrive Sunday in Taegu for the games. Pyongyang sent a telegram saying the planes carrying the athletes could not depart because of technical problems.
Pyongyang news broadcasts and a statement from North Korea's Asia-Pacific Committee gave a different reason. A North Korean broadcaster said Pyongyang would not send its athletes to Taegu because it is a "dangerous place where compatriots do harm to their brothers' safety and dignity."
The statement condemned anti-North Korea protests held in the South on Friday. Pyongyang called on South Korea to apologize for the demonstrations.
North and South Korea have carried out a number of cultural and sports exchanges since their leaders held a summit three years ago. The events have continued over the past 10 months, despite rising tensions over Pyongyang's nuclear weapons program, which violates several international accords, including a pact with Seoul to keep the Korean Peninsula free of nuclear weapons.
The two Koreas technically remain at war because the hostilities in the Korean War ended with an armistice, not a peace treaty.