WASHINGTON (Reuters) - General Motors Co's (>> General Motors Company) Cadillac brand is at least four years away from introducing a small sport-utility vehicle which is a critical part of expansion plans, the brand's president said on Thursday.

"Product development life cycles being what they are, I don't have a date in mind but I would estimate it is at least four years away," Cadillac President Johan de Nysschen told reporters at the Washington Auto Show.

The small SUV will be priced less than the larger Escalade SUV, which has a starting list price of nearly $68,000. The smaller SUV is part of Cadillac's planned $12 billion new model offensive over the next five years that will include eight vehicles. Cadillac also currently sells a mid-size SUV, the SRX, which is priced from just over $38,000.

GM has labored for years to rebuild Cadillac into a global brand, but it has stumbled as it tried to re-establish its stature in the U.S. market, where sales declined 6.5 percent last year. Globally, Cadillac sales increased 5 percent.

Small luxury SUVs are a fast-growing segment in the United States, China and Europe. Cadillac's main rivals, including Ford Motor Co's Lincoln brand already have small luxury SUVs in the market.

De Nysschen said the strong dollar would hurt Cadillac and other U.S.-based manufacturers as Asian and European competitors can be expected to use the currency advantage to cut prices.

De Nysschen also said the automaker's flagship CT6 sedan will be unveiled on March 31 at the New York Auto Show.

The CT6, which heralds a new naming scheme of letters and numbers that will be adopted across the Cadillac brand, is aimed at competing with models from BMW (>> Bayerische Motoren Werke AG) and Daimler's (>> Daimler AG) Mercedes-Benz.

He declined to say how much the CT6 would cost but he did say it would be the most expensive car in Cadillac's lineup.

De Nysschen said he expects Cadillac sales to be flat in 2015, partly because a raft of new products will not start hitting showrooms until late 2017.

He said Cadillac will produce diesel-powered cars and SUVs, which are popular in Europe, starting in 2019.

"If you want to play in Europe, you better have some diesels," de Nysschen said.

"Come along the next decade I want to start pushing more strongly into Europe," he said, adding that diesels would also be offered for sale in the United States.

(Reporting by Eric Beech; Editing by Chris Reese)