Government may be readying long-range missile launch soon, reports say

North Korea may be preparing to launch a long-range missile as soon as within a week, Japan's Kyodo news agency reported early on Thursday, citing an unnamed Japanese government official.

The official cited signs of possible preparations for a missile launch, based on analysis of satellite imagery of the North's Tongchang-ri missile test site on its west coast.

The report came as U.N. Security Council members discuss fresh sanctions against the North after it conducted its fourth nuclear test on Jan. 6. The North is already under sanctions for its nuclear and missile programmes.

North Korea last conducted a long-range rocket launch in late 2012, successfully putting into orbit an object it claimed was a communications satellite, in what experts saw as part of an effort to build an intercontinental ballistic missile (ICBM).

South Korean Defence Ministry spokesman Kim Min-seok declined to comment on whether there were pre-launch activities at the site, citing a policy of not discussing intelligence matters. However, he said the North had issued no international warnings on navigation, as it has ahead of previous long-range rocket launches.

South Korea's Yonhap news agency cited a government source as saying there had been steady activity at the missile base, with screens set up at key areas, probably to deter spy satellite surveillance.

Much of the site's operation is automated and rails are set up to move rocket components quickly for final assembly and launch, Yonhap quoted the source as saying.

The site was upgraded last year to accommodate the launch of a longer-range rocket, experts have said.

Isolated North Korea says it has a sovereign right to run a space programme and its long-range rockets are built to deliver satellites into space.