UPDATE1: N. Korea stresses legitimacy of nuclear, missile development.

BEIJING, May 6 Kyodo

(EDS: MORE DETAILS, BACKGROUND)

North Korea on Sunday reiterated the legitimacy of its nuclear and missile programs as it denounced a joint statement issued by the five permanent members of the U.N. Security Council demanding that Pyongyang refrain from carrying out a nuclear test.

''This is a grave illegal action of violating the sovereignty of the DPRK and its right to use space and nuclear energy for peaceful purposes,'' North Korea's Foreign Ministry said in a statement carried by the official Korean Central News Agency. DPRK is the acronym for North Korea's official name.

The KCNA report did not touch on the call made by the five permanent members of the Security Council for Pyongyang to refrain from conducting a third nuclear test, following tests in 2006 and 2009.

Britain, China, France, Russia and the United States issued the statement in Vienna on Thursday during a U.N. nuclear nonproliferation conference.

''The DPRK, depending on its nuclear deterrence for self-defense, will firmly protect its sovereignty and dynamically push forward the development of space for peaceful purposes and the industry of nuclear energy,'' the North Korean Foreign Ministry statement said.

North Korea tried unsuccessfully to place a satellite in orbit in April. According to South Korea's Defense Ministry, North Korea has made preparations for a nuclear test.

South Korean defense officials believe the nuclear test could take place at any time once the North Korean leadership gives the go-ahead.