SEOUL, South Korea — North Korea, which has conducted two nuclear tests in the past, on Saturday welcomed the new year with calls for a Korean peninsula free of nuclear weapons, better ties with rival South Korea and a promise to boost its military strength.

The North’s annual New Year’s message comes in the wake of its Nov. 23 artillery attack on a front-line South Korean island near the Koreas’ disputed western sea border.

That barrage, which followed an alleged North Korean torpedoing of a South Korean warship in March, sent tensions between the Koreas soaring and fueled fears of war during the last weeks of 2010.

In the holiday message, carried in the official state press, the North said confrontation between the two Koreas should be defused as early as possible and called for a more determined campaign to improve inter-Korean relations and reunify the country.

But Pyongyang also said the military would continue to prepare itself for fighting and would focus on refining its spirit through "prompt, merciless and annihilatory action."

"The entire army should conduct intense combat training in an atmosphere of actual battle as required by the tense situation so as to reliably prepare all the officers and men," the North said in the editorial carried by its leading newspapers.

Four South Koreans, including two civilians, were killed in the shelling of Yeonpyeong island, which North Korea carried out after warning Seoul against conducting live-fire drills there. The attack was the first on a civilian area since the 1950-53 Korean War.

The South Korean government has strengthened security and deployed additional troops and weaponry to Yeonpyeong, which lies just seven miles from North Korean shores.

North Korea does not recognize the maritime border drawn by the U.N. in 1953, and it claims the waters around the island as its own. The Korean peninsula remains technically in a state of war because the conflict ended in a truce, not a peace treaty.

In the New Year’s message, the North said its military "will not in the least pardon those who impair our absolute dignity and socialist system even a bit and violate our airspace, territory and waters even an inch, but discharge at any cost the historic mission it has assumed on behalf of the country and the nation with matchless arms."

The North said that leader Kim Jong Il "propelled" the country last year toward strength and success.

At the same time, the North said in an editorial that the North "is consistent in its stand and will to achieve peace in Northeast Asia and denuclearization of the whole of the Korean peninsula."

Nuclear disarament-for-aid talks among the United States, the Koreas, Japan, China and Russia have been stalled, with Washington and Seoul demanding the North fulfill past nuclear commitments before they start again.