U.S. safety regulators are adding two models to an investigation of Ford Motor Co. door latches that may not close properly.

The National Highway Traffic Safety Administration said Tuesday it's including the 2013 Ford Fusion and Lincoln MKZ midsize cars to the probe of latches on 2011-2013 Ford Fiesta compact cars. The investigation now covers nearly 486,000 cars.

Ford and the agency have received 640 complaints about the latches. Some said the doors opened inadvertently while the cars were moving. Two injuries were reported. Ford also has received nearly 1,100 warranty claims.

The agency began investigating the Fiesta in September, and found out that the other two models have the same latches.

Investigators will analyze complaints and see how often the problem happens to determine if a recall is needed.