N. Korea threatens South with "sea of fire"

Updated 6:06 PM EST

SEOUL, South Korea - North Korea threatened Thursday to turn Seoul's presidential palace office into a "sea of fire," stepping up its rhetoric one day after South Korea conducted large-scale military drills near a front-line island attacked by North Korea last year.

On Wednesday, South Korea mobilized aircraft, rocket launchers, artillery guns and naval boats for the first anniversary of the artillery attack on a military garrison and fishing community on Yeonpyeong Island in the Yellow Sea. Two marines and two construction workers were killed in the attack, the first on a civilian area since the 1950-53 Korean War.

A similar "sea of fire" threatens to engulf Seoul's presidential Blue House if South Korean forces fire a single shot into North Korean territory, the North's People's Army warned in a statement from Pyongyang.

Pyongyang accuses Seoul of provoking last year's attack, saying it struck after warning the South not to hold live-fire drills in the disputed waters. South Korea has said it fired shells southward, not toward the North, as part of routine exercises last year.

"If they dare to impair our dignity again, the deluge of fire on Yeonpyeong Island will lead to the sea of fire in Blue House" in Seoul, the North's People's Army warned in a statement from Pyongyang. "They should not forget the lesson taught" by the island shelling.

If provoked again like last year, the North's military will launch merciless, annihilating and more powerful strikes to "blow up the island without any trace," the North's Committee for the Peaceful Reunification of Korea said in a separate statement later Thursday.

Both statements were carried by the official Korean Central News Agency.

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The North has issued similar threats over years at times of tension with South Korea.

The Korean peninsula remains in a technical state of war because their conflict ended in a truce, not a peace treaty. However, North Korea disputes the maritime border drawn by the U.N. in 1953, and the waters have been a flashpoint for violence over the years.

Since then, South Korea has spent millions of dollars beefing up its arsenal. Joint Chiefs of Staff chairman Jung Seung-jo said his forces would "crush the enemy" if they strike again.

Wednesday's maneuvers took place off Baengnyeong Island, South Korean-held territory near the maritime border. The drills were meant to send a strong message to North Korea but did not include live-fire exercises, military officials said.

Relations between the two Koreas sank to the their lowest point in years in 2010 after two incidents — the shelling of Yeonpyeong Island and the sinking of a South Korean warship that killed 46 sailors. Pyongyang denies involvement in the sinking.

However, there have been some signs tensions are easing, with both sides seeking to discuss ways to resume nuclear disarmament-for-aid talks and allowing South Korea's religious and cultural figures to travel to North Korea. On Thursday, a group of South Korean scholars visited the North Korean border town of Kaesong for a joint project of recovering and preserving the site of an ancient palace.

South Korean President Lee Myung-bak said Wednesday during a visit to a military command that he was sorry North Korea had not yet apologized for the shelling. He said Pyongyang must apologize if it wants relations to improve.

Wednesday's maneuvers took place off Baengnyeong Island, South Korean-held territory near the maritime border. The drills were meant to send a strong message to North Korea but did not include live-fire exercises, military officials said.

Relations between the two Koreas sank to the their lowest point in years in 2010 after two incidents: the shelling of Yeonpyeong Island and the sinking of a South Korean warship that killed 46 sailors. Pyongyang denies involvement in the sinking.

However, there have been some signs tensions are easing, with both sides seeking to discuss ways to resume nuclear disarmament-for-aid talks and allowing South Korea's religious and cultural figures to travel to North Korea. On Thursday, a group of South Korean scholars visited the North Korean border town of Kaesong for a joint project of recovering and preserving the site of an ancient palace.

South Korean President Lee Myung-bak said Wednesday during a visit to a military command that he was sorry North Korea had not yet apologized for the shelling. He said Pyongyang must apologize if it wants relations to improve.