A live-firing exercise by South Korea passed without incident despite threats from North Korea of “catastrophic retaliation” if it went ahead.
There was no immediate sign of any North Korean military response during the drill.
The South evacuated hundreds of residents near its land border with the North and sent residents of islands near disputed waters into underground bunkers amid fears of war.
UN diplomats meeting in New York failed to find any solution to the crisis, but there was some sign of diplomacy, as a high-profile American governor announced what he said were two nuclear concessions from the North.
The live-fire exercises came nearly a month after the North responded to earlier manoeuvres by shelling Yeonpyeong island, killing two marines and two civilians in its first attack targeting civilian areas since the 1950-53 Korean War.
Pyongyang had said it would respond even more harshly to any new drills from the Yellow Sea island, though it added that its strikes would be “unpredictable.”
The drills on Yeongpyeong, a tiny enclave of fishing communities and military bases about seven miles from North Korean shores, involved several types of weapons.
The North considers waters around Yeonpyeong its own territory. Similar drills on November 23 sparked the North’s artillery barrage, after Pyongyang said the South ignored clear warnings to halt the firing.
The UN Security Council failed on Sunday to agree on a statement to address rising tensions.
The US and others wanted the council to condemn North Korea for attacks that have helped send relations between the Koreas to their lowest point in decades. But diplomats said China, the North’s major ally, strongly objected.