North Korea ready to launch missile

North Korea's long-range rocket, scheduled to put what it says is a satellite into orbit next week, has been installed on its launch platform, the country's space officials say.

Engineers said on Sunday that the satellite will orbit the earth and send back data for weather forecasts and crop surveys.

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. The US, Japan, Britain and other nations have urged the isolated nation to cancel the launch, warning that firing the long-range rocket would violate UN resolutions and North Korea's promise to refrain from engaging in nuclear and missile activity. South Korea said its army is preparing for any threats.

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 neighbours 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.