NAGOYA (Kyodo) Toyota Motor Corp. said Tuesday it has frozen a joint project with Isuzu Motors Ltd. to develop a diesel engine for small vehicles as it moves to curb research and development costs amid the global economic slump.

It is also planning to postpone the opening of a new Prius factory it is building in Mississippi to beyond 2010 or 2011.

The diesel engine that was being jointly developed with Isuzu was originally scheduled to be installed in small cars to be sold in Europe, where fuel-efficient diesel cars are highly popular.