South Korea warned Pyongyang on Thursday that a firing long-range rocket would be "a serious challenge and provocation" threatening regional stability, as a report said North Korea is "technically" three to four days away from a launch.
North Korea, which has declared its intention to shoot a communications satellite into space between April 4 and 8, has mounted a rocket onto a launched in the northeast, US counter proliferation and intelligence officials said.
Pyongyang has asserted its right to develop its space program, but regional powers suspect the North will use the launch to test its long-range missile technology. They have warned that the launch banned by the UN Security Council in 2006 would trigger international sanctions.
US spy satellites detected the rocket on the launched in Musudan-ni two days ago, earlier than US and South Korean intelligence officials had expected, South Korea's Chosun Ilbo newspaper said on Thursday.
With the rocket in place, it is "technically possible" for the North to launch it in three to four days, the report said, citing an unnamed diplomatic source in Seoul.
The Defence Ministry said it could not confirm the rocket's placement.