Raytheon and Lockheed Martin are working with Japanese partners on rival projects to develop new radars that will enhance Japan's shield against any North Korean missile strike, government and defense industry sources in Tokyo said.

As nuclear-armed Pyongyang builds ever more advanced missiles with the ability to strike anywhere in Japan, Tokyo is likely to fund a ground version of the ship-based Aegis defense system deployed on warships in the Sea of Japan, other sources said earlier.

Raytheon is allied with Mitsubishi Electric on the project while Lockheed is working with Fujitsu. The intent is to extend the range of Japan's detection and targeting radars multiple times beyond the range of models currently deployed at sea, the five government and industry sources said.