Toyota's president Katsuaki Watanabe has said his company’s discussions with General Motors on fuel-cell vehicles are in their final stages.

They jointly run a vehicle assembly plant (known as NUMMI) in California and a 1999 technology-sharing agreement is still in place.

"We are in the final stages of the talks," Watanabe said at the company's Tokyo office. "It's better not to let the talks drag on."