PYONGYANG: North Korea vowed Monday to strengthen its defenses amid concerns the country may conduct a nuclear test as a follow-up to last month's long-range rocket launch.

Citing U.S. hostility, Pyongyang's Foreign Ministry said in a memorandum that North Korea will "continue to strengthen its deterrence against all forms of war."

The memorandum carried by state media did not say what action North Korea would take to defend itself. However, North Korea has claimed the right to build atomic weapons to protect itself from the United States, which stations more than 28,000 troops in South Korea.

North Korea sent a satellite into space on Dec. 12 aboard a long-range rocket, a launch that the U.S. and its allies have criticized as a test of banned ballistic missile technology.

In 2006 and 2009, Pyongyang conducted atomic tests after being slapped with U.N. Security Council condemnation and sanctions for similar launches of long-range rockets.

North Korea's Foreign Ministry urged the Washington to dismantle the U.S.-led U.N. Command, which oversees an armistice signed at the close of the Korean War in 1953. It accused the U.S. of trying to turn the U.N. Command into a NATO-like regional military bloc.

"Whether the U.S. immediately dismantles the U.N. Command or not will serve as the acid stone in deciding whether the U.S. will maintain or not its anti-(North Korea) hostile policy," said the memorandum, which was carried by the official Korean Central News Agency.

The Korean War armistice was never replaced with a peace treaty, leaving the Korean Peninsula in a technical state of war 60 years later.