President Lee Myung-bak ordered a stern response to North Korea's artillery attack Tuesday, which killed at least one soldier and wounded about a dozen others, including civilians, Lee's office Cheong Wa Dae said, Yonhap reported.
"Deal resolutely (with the attack) but make all-out efforts not to aggravate the situation," Lee was quoted as saying in an emergency meeting with his senior secretaries.
The attack killed one South Korean marine and wounded 13 others, according to military authorities. It also wounded some residents and set houses and forests on fire in Yeonpyeong Island, just south of the Northern Limit Line, the de-facto sea border between the two Koreas drawn at the end of their 1950-53 war.
South Korea's military immediately fired back, and the crossfire continued for about an hour. Military sources said the firings appear to have stopped.
Cheong Wa Dae said the president was currently presiding over an emergency meeting of security-related ministers at an underground bunker at the presidential compound to discuss countermeasures. Participants include Foreign Minister Kim Sung-hwan, Unification Minister Hyun In-taek, Defense Minister Kim Tae-young and Won Sei-hoon, chief of the state spy agency.
Cheong Wa Dae spokeswoman Kim Hee-jung told reporters earlier that the North's provocation might have come in retaliation for one of the South's annual military exercises.
"Our Navy was conducting a maritime exercise near the western sea border today. North Korea has sent a letter of protest over the drill. We're examining a possible link between the protest and the artillery attack," said Kim.
Officials said the government was in talks with the United Nations and considering whether to refer the North's attack to the global body.
All of some 1,600 residents of Yeongpeyong Island have been evacuated, and all public servants have been put on standby.