North Korea could eventually reach US with nuclear arms - Pentagon report

North Korea's continuing development of nuclear technology and long-range ballistic missiles will move it closer to its stated goal of being able to hit the United States with an atomic weapon, a new Pentagon report to Congress said on Thursday.

The report, the first version of an annual Pentagon assessment required by law, said Pyongyang's Taepodong-2 missile, with continued development, might ultimately be able to reach parts of the United States carrying a nuclear payload if configured as an intercontinental ballistic missile.

North Korea launched a multi-stage rocket that delivered a satellite into orbit in December, an advance that "contributes heavily" to the country's development of a long-range ballistic missile capability, the report said.

It is also continuing to refine its atomic weapons capability, including with a nuclear detonation in February, and is capable of conducting "additional nuclear tests at any time," the report said.

"These advances in ballistic-missile delivery systems, coupled with developments in nuclear technology ... are in line with North Korea's stated objective of being able to strike the U.S. homeland," the report said.

"North Korea will move closer to this goal, as well as increase the threat it poses to U.S. forces and allies in the region, if it continues testing and devoting scarce regime resources to these programs," it said.

The document characterized North Korea as one of the biggest U.S. security challenges in the region because of its effort to develop nuclear arms and missiles, its record of selling weapons technology to other countries and its willingness to "undertake provocative and destabilizing behaviour."

The report comes at a sensitive time in the region, with friction between Washington and Pyongyang only now beginning to ease following two months of increasingly shrill rhetoric that seemed to edge the Korean peninsula close to war.

Tensions between the two countries rose sharply after North Korea put the satellite into space in late December and conducted the nuclear test in February. The test triggered new U.N. sanctions, which led to a barrage of threats from Pyongyang.

North Korea went so far as to warn of nuclear strikes on the United States and South Korea, as its new leader, Kim Jong-un, marked his first year in office following the death of his father.

The U.S. and South Korean militaries went ahead with a long-scheduled military exercise despite the threats and Washington sending stealth bombers and other planes to the region in a show of force.

North Korea signed a deal to get rid of its nuclear program in exchange for aid in 2005 but later backed out of the pact and now says it will not give up its atomic weapons program.

The United States has firmly rejected North Korean demands that it be recognized as a nuclear-armed state. Washington has stepped up its diplomacy with China over the issue.