By Kim Young-jin

North Korea ratcheted up tensions Thursday over South Korean military drills near the hotly-contested maritime border a day earlier, threatening to turn Cheong Wa Dae into a “sea of fire.”

The rhetoric came a day after the South conducted a major military drill near the sea border to mark the first anniversary of the North’s deadly shelling of Yeonpyeong Island that sent inter-Korean tensions soaring.

In a statement carried by its official Korean Central News Agency, Pyongyang said it would carry out its threat if even a single shot from the South entered its territory. The Stalinist state issues similar threats to the city of Seoul with regularity.

It reminded South Koreans of the tension that engulfed the peninsula in the wake of the shelling that killed two Marines and two civilians on the tiny fishing island. The North claims it was goaded into the attack by military drills that Seoul says were routine.

On Wednesday, while the nation observed the anniversary, the South mobilized aircraft, artillery, rocket launchers and other weapons to the nearby island of Baengnyeong while vowing to “crush the enemy” in response to any provocation. Officials said the drill did not include live-fire exercises.

The threat to Cheong Wa Dae comes after the North had held back on its nasty rhetoric against the Lee Myung-bak administration amid efforts to cool tensions and resume multilateral denuclearization negotiations.

“It was a warning to the South not to make any ‘provocations’ against the North,” said Yoo Ho-yeol, a North Korea expert at Korea University. “While the South sees the drills as deterrence, the North probably feels threatened by the increased capabilities on the border islands.”

Seoul and Pyongyang have held two rounds of talks in recent months in a bid to restart the six-party nuclear talks that also include the United States, Japan, Russia and China.

Yoo added that the North — ultimately seeking aid — could have been trying to bolster its position ahead of further talks with the inflammatory remark.

“It seems to be a tactic to show that they have other reasons besides securing aid to hold dialogue. They want to remind Seoul that they have their own ways to apply pressure.”

Analysts say Pyongyang is doing all it can to gather resources ahead of next year, when it has promised to emerge as a “strong and prosperous state.”

The two sides remain technically at war since their 1950-53 fratricidal conflict ended in a truce, not a peace treaty. Pyongyang has long contested the maritime border established by the United Nations.

Since the attack, the South has bolstered its readiness in the West Sea, updating its plans to deal with contingencies and rules of engagement and announcing it will complete a joint operational response plan with the United States.