President Barack Obama has visited the Demilitarized Zone (DMZ) separating South Korea from North Korea, amid rising tensions over the North’s planned rocket launch.
Barack Obama went to an observation post on the volatile border, and met US troops. The president will hold talks in Seoul later.
The US has voiced concern that the North Korea’s rocket launch due in April is a pretext for a missile test. Pyongyang says it wants to put a satellite into orbit.
On Monday, Barack Obama will attend a security summit in Seoul.
The conference in the South Korean capital will be attended by leaders from more than 50 nations.
The summit main focus will be preventing criminal or militant groups from acquiring nuclear weapons.
Pyongyang’s nuclear programme is not officially on the agenda. But American officials have made it clear that President Barack Obama will be discussing the programmes of both North Korea and Iran in bilateral meetings with the Chinese and Russian presidents, our correspondent says.
North Korea is not taking part in the summit.
President Barack Obama has visited the Demilitarized Zone (DMZ) separating South Korea from North Korea, amid rising tensions over the North's planned rocket launch
It was Barack Obama’s first visit to the DMZ, which has bisected the peninsula since the end of the Korean War in 1953.
The president told US troops serving there that they were protecting “freedom’s frontier”.
Earlier this week, Japan said it was readying its anti-missile defenses ahead of North Korea’s launch, expected between 12 and 16 April.
Pyongyang says the rocket – which would mark the 100th birthday of its late Great Leader Kim Il-Sung – would take a new southern trajectory instead of a previous route east over Japan.
US Assistant Secretary of State Kurt Campbell has said an area between Australia, Indonesia and the Philippines could be affected by the flight path.
North Korea has shown a growing mastery of ballistic technology during its three previous long-range tests.
However, experts say none has succeeded in reaching orbit, and debris has fallen to earth at various stages during the launches.
Last month North Korea offered a deal involving the freezing of its nuclear and long-rang missile programmes in return for US food aid.
North Korean rocket due to be launched in April may affect an area between Australia, Indonesia and the Philippines, says US Assistant Secretary of State Kurt Campbell.
Kurt Campbell is reported to have asked the three countries to condemn the launch.
North Korea says the rocket will take a new southern trajectory instead of a previous route east over Japan.
Japan is readying anti-missile defenses around the southern islands of Okinawa, which could be under the flight path.
North Korea says the rocket is intended to put a satellite in space, but the US and others say the launch is a cover for a long-range missile test – a potential delivery system for nuclear weapons.
The launch is expected to dominate a security summit on Monday in the South Korean capital Seoul, which will be attended by US President Barack Obama.
North Korean rocket due to be launched in April may affect an area between Australia, Indonesia and the Philippines
Australia’s Sydney Morning Herald said Kurt Campbell had briefed Australian Foreign Minister Bob Carr on Friday on the rocket’s southward trajectory.
“If the missile test proceeds as North Korea has indicated, our judgment is that it will impact in an area roughly between Australia, Indonesia and the Philippines,” the paper quoted Kurt Campbell as saying.
“We have never seen this trajectory before. We have weighed into each of these countries and asked them to make clear that such a test is provocative and this plan should be discontinued.”
Pyongyang appears to be trying to soften the political impact of its planned rocket launch.
It has chosen a new southerly route mainly over open sea, avoiding what is regarded as a more provocative easterly trajectory over the main Japanese island.
North Korean state-run KCNA news agency said: “A safe flight orbit has been chosen so that carrier rocket debris to be generated during the flight would not have any impact on neighboring countries.”
North Korea has shown a growing mastery of ballistic technology during its three previous long range tests.
However, experts say that none has succeeded in reaching orbit, and debris has fallen to earth at various stages during the launches.
Pyongyang said last week that the rocket launch – between 12 and 16 April – would mark the 100th birthday of its late Great Leader Kim Il-Sung.