A Japanese government spokesman, Akitaka Saiki, says intelligence reports indicate that North Korea could be preparing to launch another missile.

Mr Saiki said the government did not have any information on when such an event might take place.

His comments follow newspaper reports in Japan that Tokyo had been warned by the United States of equipment movements in North Korea similar to those detected before Pyongyang fired a missile over Japan in August.

North Korea says that launch was of a rocket to put a satellite in orbit.