Updated from Tuesday, Nov. 23

SEOUL, SOUTH KOREA (

TheStreet

) -- Two civilians were found dead Wednesday on the island hit by the North Korean artillery attack the day before, the first civilian deaths recorded from the bombing, the coast guard said,

Yonhap News Agency

reports.

The deaths brought the number of victims in Tuesday's attack to four, including two marines. Eighteen others, including three civilians, were wounded,

Yonhap

reports.

North Korea fired about 170 artillery shells toward the South Korean island near their border Tuesday, killing the two South Korean marines.

Update: U.S., South Korea Launch War Games >>

South Korea's military returned fire and lobbed more than 80 shells toward North Korean artillery positions. South Korea also deployed fighter jets to the island and placed all its troops on maximum alert, said the officials.

The exchange of fire Tuesday lasted for about a hour.

President Lee Myung-bak ordered his military Tuesday to punish North Korea for its artillery attacks "through action," not just words, saying it is important to stop North Korea from contemplating additional provocation,

Yonhap

reports.

"The provocation this time can be regarded as an invasion of South Korean territory. In particular, indiscriminate attacks on civilians are a grave matter," Lee said Tuesday.

Some residents on Yeonpyeong Island, which lies just south of the maritime border between the two Koreas, were wounded and houses and forests were on fire, according to

Yonhap

.

"Given that North Korea maintains an offensive posture, I think the Army, the Navy and the Air Force should unite and retaliate against (the North's) provocation with multiple-fold firepower," Lee said,

Yonhap

reports. "I think enormous retaliation is going to be necessary to make North Korea incapable of provoking us again."

Yonhap

said North Korea's attack marks the fiirst direct artillery attack on South Korean territory since the Korean War ended in an armistice, not a formal peace treaty.

North Korea's military command, meanwhile, vowed a "merciless" military strike against South Korea. In a statement carried by the official Korean Central News Agency, North Korea accused the South Korean military of initiating the exchange by shooting toward its side.

"Should the South Korean puppet group dare intrude into the territorial waters of the (North) even 0.001 mm, the revolutionary armed forces of the (North) will unhesitatingly continue taking merciless military counter-actions against it," the statement said,

Yonhap

reports.

The White House, in a statement Tuesday, said "The United States strongly condemns this attack and calls on North Korea to halt its belligerent action and to fully abide by the terms of the Armistice Agreement. The United States is firmly committed to the defense of our ally, the Republic of Korea, and to the maintenance of regional peace and stability."

South Korea and the United States will launch a joint naval drill in the Yellow Sea from Sunday with a nuclear-powered American aircraft carrier taking part, officials said Wednesday,

Yonhap

reports.

The four-day exercise had been planned well before the North's artillery attack.

-- Written by Joseph Woelfel

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