Nissan is halting joint development of luxury cars with Daimler's Mercedes-Benz, sources close to the companies told Reuters, suspending a key project in their seven-year partnership and potentially hitting profitability at a new shared factory in Mexico.

Nissan decided in October its premium Infiniti brand would not use MFA2, an upgraded Daimler car platform that the companies have jointly funded, in part because Infiniti was not performing well enough to absorb Mercedes technology costs, the sources said.

"It wasn't possible to close a deal on the basis of MFA2," said one of the people. "The targets set by Infiniti were too difficult to achieve."