MOSCOW, November 10 (RIA Novosti) - The...

The South Korean news agency quoted a navy official as saying a North Korean patrol vessel crossed the border and prompted South Korea to fire warning shots.

"It wasn"t a close-range battle. We fired heavily on the North Korean vessel," the official, who declined to be identified, said, adding that no South Koreans were killed. "The North Korean boat suffered considerable damage."

Another official said the North fired back.

In 1999 and 2002 deadly clashes occurred along the disputed demarcation line, called the Northern Limit Line, which was unilaterally drawn by the United States in 1953 and is not recognized by North Korea.

Nonlethal armed incidents have occasionally taken place in the area.