"Satellite images show our shells landed on a cluster of barracks in North Korea, so we presume there have been many casualties and considerable property damage," said a senior official at the South's Joint Chiefs of Staff (JCS).
The South is still analyzing images taken by its own satellite to assess the extent of damages and casualties on the North's side, the official said on the condition of anonymity. He declined to elaborate further, but the remarks were the military's first mention of human casualties in North Korea.
Earlier in the day, a lawmaker suggested there were probably "severe human casualties" in North Korea, citing satellite images showing that counterfire by South Korea's military hit hard one of the North's barracks near the tense Yellow Sea border.
The North's daylight artillery bombardment left four people dead, including two civilians, on Yeonpyeong Island, the first strike on a civilian area since the 1950-53 Korean War. South Korean marines on the island shot back with some 80 rounds minutes after the North's shelling.
"About 10 artillery shells fired by our military landed onto a military unit compound on Mu-do (in North Korea) and one of them directly hit a barrack," said Rep. Kwon Young-se of the ruling Grand National Party, citing two satellite images provided by the nation's spy agency. Kwon is the head of the National Assembly's intelligence committee.
"There might have been severe human casualties," Kwon told reporters after a parliament committee meeting with officials from the National Intelligence Service (NIS). Mu-do is a small island north of the Yellow Sea border from where a North Korean artillery battalion launched the attack.
Photo of North Korean island Mu-do taken on Nov. 26 (Yonhap)
The NIS told lawmakers that, out of the 80 rounds, 15 shells fell onto Mu-do and another 30 landed onto Kaemori, another North Korean area from where the artillery attack was also launched, Kwon said.
Meanwhile, the military denied a reported remark by the NIS chief who said that wiretaps in August had uncovered North Korea's plan to attack South Korea's border islands.
NIS Director Won Sei-hoon reportedly told lawmakers Wednesday that the South confirmed through electronic surveillance back in August that the North was planning to launch an attack against one of the five Yellow Sea islands.
The remark by Won sparked media outrage over a lack of intelligence and combat readiness by the military.
"It's not true that there was intelligence indicating North Korea might attack the five islands in the Yellow Sea," a JCS official said, adding the spy chief's remark was incorrectly reported.
"The intelligence in August was on the North Korean military's order to fire artillery against our military drill," the official said.
A marine unit on Yeonpyeong held artillery firing drills on Aug. 6 and Aug. 8, and North Korea fired shells into the South Korean waters on Aug. 9, the official said.
In a closed-door parliamentary meeting on Wednesday, the spy chief said that his government has "had such analysis" that the North was plannint to launch an attack on Yellow Sea islands.
During the meeting, Won also told lawmakers that North Korea is highly likely to attack South Korea again.