North Korea has been using Russian technology in developing a new intercontinental ballistic missile capable of reaching any target in the continental United States, an administration official said yesterday. The official, asking not to be identified, estimated the potential range at 15,040km. The distance from Pyongyang, the North Korean capital, to San Francisco is about 8,800km. In theory at least, the new missile could strike any target on US soil, a potential that becomes all the more ominous if Pyongyang is able to cap the rocket with a nuclear warhead, the official said. There were indications that North Korea planned to exhibit the missile - as well as models from the country's existing system - during National Day festivities on Tuesday but did not do so, the official said. The official said the development is significant because it demonstrates co-operation from Russian entities or scientists. The Bush administration has raised the issue with Russian government officials, who indicated surprise and disapproval of the activity, the official said. According to the official, the missile is based on Russia's SSN6, a Soviet-era submarine-launched ballistic missile. Two weeks ago, officials from North Korea and the US, along with China, South Korea Japan and Russia, met in Beijing to discuss ways of surmounting the impasse over the North's nuclear weapons system. **PHOTO CAPTION*** A little girl pedals her tricycle past a stack of scrapped missiles, South Korean's Nike (L), US's Hawk (C) and North Korea 's Scud, put on display at a war museum in Seoul(AFP/Choi Jae-Ku)