SEOUL - NORTH Korea seems to be preparing to test-fire a medium-range missile from its south-east coast, South Korea's Yonhap news agency reported on Tuesday.

The missile is apparently being prepared for launch from a North Korean missile base in Anbyon County, about 100km north-east of Seoul, Yonhap said.

A South Korean defence ministry spokesman declined to comment on the report.

The North has launched a series of short-range missiles since its second nuclear test on May 25. US and South Korean officials have said there are signs that it may also be preparing to test-fire a long-range missile.

Tensions have mounted after Kim Jong Il's regime tested a nuclear bomb last week for the second time and then launched a series of short-range missiles and threatened possible attacks on South Korea.

Pyongyang has warned it would take 'self-defence measures' in response to any tougher international sanctions over its May 25 nuclear test.

South Korea said on Monday that a long-range missile launch appeared possible. 'We have detected signs that North Korea is preparing to fire an ICBM (intercontinental ballistic missile),' a defence ministry spokesman said.

The North has another launch site on the east coast at Musudan-ri, from where it fired a Taepodong-2 rocket over Japan in April. It said the launch was to put a satellite in orbit but other nations saw it as a disguised missile test.

US defence officials last week reported vehicle activity that suggested the North may be preparing to launch a long-range missile.

'We have seen some signs that they may be doing something with another Taepodong missile but at this point it's not clear what they're going to do,' US Defence Secretary Robert Gates told reporters in Manila on Monday. -- AFP