Nissan Motor Co. is squeezing all it can from its U.S. assembly plants and will need to build an entirely new factory if it keeps growing in the lucrative American auto market, a top executive said.

"At some point, we may need it," Jose Munoz, chairman of Nissan North America, said in an interview, referring to additional production capacity. The addition would have to be a standalone new factory because the company's existing assembly plants in Tennessee and Mississippi are "maxed out," he said.

Building another factory in the U.S. would likely appease President Donald Trump, who's pressuring Japanese car manufacturers for more of the millions of vehicles they sell in America each year to be built locally. While Nissan already has the most productive auto plant in all of North America in Smyrna, Tennessee, the company also imports several models from Japan and is the top car producer in Mexico.

Nissan's U.S. sales have increased about 70 percent over the last six years, and the automaker's strategic plan through 2022 calls for further expansion, Munoz said in Detroit.

The company sold about 1.6 million cars and trucks in the U.S. last year.

More than 8,000 workers make cars and battery packs at Nissan's Tennessee complex that produced more than 640,000 vehicles last year, including Leaf electric cars, Altima and Maxima sedans and Infiniti QX60 sport utility vehicles. Its Mississippi operation employs 6,400 people making Titan pickups, cargo vans and Altima sedans, among others.

"The strategy of localization has allowed us to grow big-time in the States," Munoz said.