By Jack Kim and Ju-min Park
SEOUL (Reuters) - North Korea has started to dismantle a controversial long-range rocket on its launch pad in an apparent move to fix a technical problem but still looks likely to go ahead with the launch, South Korean news reports and experts said on Tuesday.
North Korea says the launch is to put a weather satellite in orbit but critics say it is aimed at nurturing the kind of technology needed to mount a nuclear warhead on a long-range missile.
When the first reports emerged that the rocket parts were being taken down, there was speculation the North might abandon the launch altogether, but experts said the construction of the rocket meant that it needed to be removed from its gantry.
"For North Korean rockets, it's the only way to repair them because they build the rocket stage by stage," said Kwon Se-jin, a rocket expert at the Korea Advanced Institute of Science and Technology in Daejeon, South Korea.
North Korea said on Monday that the launch window had been extended by a week due to technical problems.
"So as it had announced, if the North has a problem with the first-stage control module, it has to replace it and take down (the rocket) from the top," said Kwon.
The launch has been timed to coincide with the first anniversary of the death of former leader Kim Jong-il after a failed launch in April. It also comes as Japan and South Korea, long-time foes of the North, are holding elections.
North Korea is banned from testing missile or nuclear technology under U.N. sanctions imposed after its 2006 and 2009 nuclear weapons tests, and the United States, South Korea and Japan have condemned the current launch.
Even China, the one major diplomatic backer of isolated and impoverished North Korea, has expressed "deep concern" over the planned launch.
South Korean media reported on Tuesday that satellite images showed the rocket was being taken down.
"We have captured indications that a part of the rocket is being disassembled from the launch pad in Tongchang-ri," Yonhap news agency quoted a South Korean government source as saying.
The name refers to the North's new test site in its western region close to the border with China.
"There is no change to the North's will to fire the rocket," another source was quoted as saying by Yonhap.
Officials at South Korea's military and its foreign and defense ministries could not confirm the reports.
North Korea is assiduous in meeting its international obligations on reporting long-range rocket launches and notified international maritime and aviation bodies of its plans last week.
It was impossible to confirm the media reports in what is one of the most closed and secretive states on Earth.
(Reporting by Jack Kim and Ju-min Park; Editing by David Chance and Nick Macfie)