According to American intelligence agencies, the new missile may have a range of 15,000 kilometers, a distance within the range of any US state or territory.

Some officials said the new missile is based on Russia's SS-N-6 "Serb," a Soviet-era, submarine-launched ballistic missile. American officials say this suggests military cooperation between Russia and Pyongyang, the Associated Press reports.

North Korea was thought to have missiles capable of reaching Alaska, Hawaii and the US’ western coastline.

Meanwhile, North Korea declined Washington’s request to curtail its nuclear weapons development program. According to North Korea’s official newspaper Rodong Sinmun, the United States is trying to find a pretext for a pre-emptive nuclear strike. Before dismantling its nuclear program, Pyongyang should get the US to sign a non-aggression treaty with North Korea and normalize relations with Pyongyang. For its part, Washington is only ready to consider guaranteeing security and economic help to North Korea. The US’ demands that North Korea curtail its weapons development program are unacceptable without the signing of the non-aggression treaty. According to the newspaper, they in fact mean that North Korea should disarm and give in to Washington.

This publication appeared in the official North Korean newspaper the day after American authorities said North Korea had completed the reprocessing of spent nuclear fuel in the amount sufficient for the production of several atomic bombs.

For its part, quoting American sources, Reuters reports that North Korea appears to have halted work at its Yongbyon nuclear complex, center of efforts to produce plutonium for atomic weapons. According to the news agency, the sources said they did not know the reason, but told Reuters possibilities include: Pyongyang has done this as a gesture to encourage negotiations with Washington; run into technical difficulties, or, more ominously, finished reprocessing fuel needed for a half dozen or more nuclear bombs.

Spent nuclear fuel rods are used for the production of plutonium, a necessary component of nuclear warheads. A source in Pyongyang said in April that North Korea was reprocessing 8,000 spent fuel rods. They could be used to produce fuel for a half dozen more nuclear bombs beyond the one or two intelligence agencies say the North may have, Reuters reports.