Automakers ended the year with strong U.S. sales but forecast lower growth in 2012, as a sluggish economic recovery is expected to continue.

General Motors Co U.S. sales in December rose 5 percent, while sales at Ford Motor Co and Chrysler jumped 10 percent and 37 percent, respectively.

U.S. new-vehicle sales are an early indicator each month of consumer spending, and the United States is the world's second-largest auto market behind China.

The U.S. industry is headed for full-year 2011 sales of about 12.8 million, which would be an increase of 10 percent from 2010. However, GM, Ford and Volkswagen AG , which reported a 36 percent gain in December, all said growth would increase at a lower rate.

GM and VW expect 2012 U.S. sales in the range of 13.5 million to 14 million vehicles, which implies growth of between 5 percent and 9 percent. Ford sees a range of 13.2 million to 14.2 million, excluding medium and heavy-duty trucks.

Industry research firm expects 2012 U.S. auto sales to reach 14 million.

That is still much lower than the nearly 17 million in U.S. annual auto sales averaged in a 10-year period through 2007. In 2008, recession began to take hold and a year later GM and Chrysler filed for bankruptcy.

Over the course of the fourth quarter of 2011, clear signs emerged that U.S. consumers are more confident and that other underpinnings of our economy are either stable or slowly improving, GM U.S. sales chief Don Johnson said in a statement.

It's now clear that auto sales should continue to grow in 2012, barring a shock to the system, he added.

Jonathan Browning, who heads VW's U.S. operations, said the automaker chose to give a forecast range for 2012 sales because of uncertainties including the U.S. presidential election and the debt crisis in Europe.

It just reflects the macroeconomic volatility we see around the world, Browning said of VW's forecast. It's wise to have some flexibility in your plan.

GM's increase in December was due to strong demand in its Chevrolet brand, where sales rose almost 9 percent. Sales of the Cruze small car jumped 54 percent, while the Sonic subcompact increased 42 percent compared with its predecessor car, the Aveo.

Ford sales were helped by its best retail sales month since 2005.

The gain at Chrysler, which is controlled by Fiat , was due to a refreshed lineup of cars and trucks.

They've done a remarkable job sprucing up their vehicles, said Edmunds analyst Michelle Krebs, adding that Chrysler was coming off a low base of sales in 2010.

Krebs credited last year's halftime television ad during pro football's Super Bowl championship, featuring rapper Eminem, for raising the brand's image with consumers.

For the year, sales at Chrysler finished up 26 percent, and the automaker said it gained 1.3 percentage points of market share.

Nissan Motor Co Ltd's <7201.T> U.S. sales rose 7.7 percent in December.

The annual sales rate for December, according to a Thomson Reuters poll of 30 analysts, is expected to rise about 9 percent from a year earlier to 13.6 million vehicles, topping 13 million for the fourth straight month. The December 2010 sales rate was 12.5 million vehicles.

(Reporting by Ben Klayman, Bernie Woodall and Kevin Krolicki in Detroit;editing by John Wallace and Mark Porter)