MOSCOW, November 10 (RIA Novosti) - South Korean President Lee Myung-bak convened an emergency meeting on Tuesday after a brief exchange of gunfire between North and South Korean ships in the Yellow Sea.

The warships fired shots near a disputed sea border area, after each accused the other of illegally crossing the boundary. No one was injured.

South Korea's Yonhap news agency said Lee met with security-related ministers immediately after hearing the news.

"The president instructed the military to react decisively, yet calmly to make sure the situation does not further deteriorate," Lee Dong-kwan, a senior secretary to the president for public relations, was quoted by the agency as saying.

South Korean Prime Minister Chung Un-chan called the clash "accidental", and said: "we ask the people to have confidence in our military and government and carry on with their daily lives as usual."

The U.S. has urged North Korea to prevent tensions from rising over the incident.

White House spokesman Robert Gibbs said: "I would say to the North Koreans that we hope that there will be no further actions in the Yellow Sea that could be seen as an escalation."

U.S. President Barack Obama will visit South Korea as part of his Asian tour next week.