Volkswagen will present a sport-utility concept vehicle in the United States next month, intended to increase its range in the lucrative crossover segment and boost sales in the world's second-biggest car market, company sources said.

A five-seat variant of the seven-passenger SUV the German carmaker aims to build at its U.S. plant in Tennessee in 2016 will be unveiled at the Detroit auto show on Jan. 12-13, two sources said on Monday on condition of anonymity because details of the proposed model have not been released.

The concept vehicle, which the sources said is likely to be approved for production by 2016-17, is the latest part of VW's plan to plug gaps in a U.S. line-up that offers only two SUVs, the Tiguan and Touareg.

VW's focus on smaller vehicles, such as the Golf hatchback and the Jetta compact saloon, has held it back in the United States, where rivals offer a wider range of SUV crossovers.

The company would only say that a concept SUV will be shown in Detroit, without providing further detail.

U.S. sales of the VW brand were down 11 percent in the January to November period at 333,000 vehicles.

Bernd Osterloh, VW's top labor representative and a member of the carmaker's panel shaping U.S. strategy, acknowledged in an interview this month that the brand is not yet represented in the growing segments of the U.S. market.

"We need more models there ... If we had a pick-up truck today, we would perhaps already be at 600,000 (vehicle sales)."

Europe's largest automaker, which ranks second to Toyota in global sales, plans to spend more than $7 billion in North America by the end of 2018 in an effort to more than double sales to 800,000 cars.

The company will overhaul the Tiguan next year and add a coupe-style version as well as a long-wheelbase model that may offer a petrol-electric hybrid version.

Its crossover campaign ties in with similar plans by the group's premium marques. Porsche started selling the Macan SUV in April while luxury division Audi will start building the Q1 baby SUV in 2016.

Ultra-luxury division Bentley will expand into SUVs in 2016 while Italian supercar maker Lamborghini, also part of the VW group, is awaiting parent approval for its own SUV.

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