Tokyo, Sep 11 (DPA) Japan launched its third spy satellite Monday to watch North Korea amid concerns about its neighbour's nuclear and missile programmes.

An H-2A rocket lifted the optical satellite into space from the Tanegashima Space Centre in the southern prefecture of Kagoshima after poor weather delayed the launch Sunday, said media reports.

A fourth spy satellite outfitted with radar is to be launched this winter.

Japan decided to build spy satellites after North Korea fired a ballistic missile in 1998 that flew over Japan and landed in the Pacific.

Its first set of spy satellites were fired off in March 2003, but a second pair was lost eight months later with a failed launch of another H-2A rocket.

After the launch of the fourth spy satellite, the two pairs of eyes in the sky would be able to monitor any point on earth once a day.

Monday's launch comes two months after North Korea test-fired seven missiles into the Sea of Japan, garnering international condemnation as Pyongyang refuses to return to talks on its nuclear programme, which have been stalled since September 2005.