North Korea has moved into place a long-range rocket for a controversial launch later this month - amid reports it is also planning a nuclear test.
Pyongyang says the 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.
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.
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 neighbours 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.