North Korea has made the arrangements to put into position a long-range rocket for a controversial launch next week – amid reports it is also planning a nuclear test.
Pyongyang says the Unha-3 rocket, which it plans to launch between 12 and 16 April, will put a satellite into orbit.
But opponents of the move fear it is a disguised long-range missile test.
Meanwhile, South Korean officials say new satellite images suggest the North is preparing to carry out a third nuclear test.
The images show piles of earth and sand at the entrance of a tunnel at the Punggye-Ri site, where tests of a nuclear bomb were previously carried out in 2006 and 2009, South Korea’s Yonhap news agency reports.
“Recent satellite images led us to conclude the North has been secretly digging a new underground tunnel in the nuclear test site… besides two others where the previous tests were conducted,” one unnamed official told the AFP news agency.
North Korea has been under close scrutiny by its neighbors and the international community since Kim Jong-Un became leader of the secretive state following the death of his father, Kim Jong-Il, in December 2011.
Pyongyang had agreed in February to a partial freeze in nuclear activities and a missile test moratorium in return for US food aid. But the deal was put on hold last month after the North announced its rocket launch plans.
Foreign journalists were taken by train to the Sohae satellite station at Tongchang-Ri, on the country’s north-west coast, to see for themselves the final preparations for the rocket launch.
All three stages of the rocket were visibly in position at the launch pad, an Associated Press reporter said from the scene.
Station manager Jang Myong-Jim told reporters that preparations were on track and fueling would begin soon, without giving exact timings.
Jang Myong-Jim said the 100 kg (220 pound) satellite is designed to send back images and information that will be used for weather forecasts as well as surveys of North Korea’s natural resources, the AP reports.
Pyongyang has previously said the launch, for “peaceful purposes”, is to mark the centennial of the birth of founding leader Kim Il-Sung.
But the United States and North Korea’s neighbors say it contravenes UN resolutions that were imposed after a similar launch in April 2009.
Japan and South Korea have warned they will shoot the rocket down if it strays into their territory.