Toyota and GM are having difficulty coordinating their views on how to share intellectual property rights and handle the results of joint research, the sources said. 

This has prevented them from entering into negotiations on the specifics of the proposed joint venture, they said. 

Fuel cell technologies are also highly sensitive militarily, and the U.S. government may limit U.S. companies in disclosing such technologies to foreign firms, they added. 

GM Chairman Rick Wagoner visited Nagoya in May and talked with then Toyota President Fujio Cho about the possibility of a tie-up in environmental technology. 

Since then the two companies have been considering ways to boost their cooperation in developing environmentally friendly cars, including ones powered by fuel cells.
 
New Toyota President Katsuaki Watanabe has said Toyota and GM should make a decision quickly on the proposed joint venture. 

But it is uncertain whether the two companies will be able to strike an early deal due to the stalled negotiations, the sources said. 

Industry observers said that if GM, the world's No. 1 automaker, and Toyota, No. 2, join forces, it would spur the commercialization of fuel cell technologies. Their technologies may also become global standards, they said. 

Through cooperation with GM, Toyota is also apparently trying to avert auto trade friction between Japan and the United States that may reemerge with increasing sales of Japanese cars on the U.S. market, they said.