General Motors Chief Executive Rick Wagoner told investors Tuesday that the automotive giant will close down four truck and SUV factories in North America, increase production of fuel-efficient cars, and is considering the possible sale of its Hummer unit. 

The announcements come as GM (GM) and the American consumer deal with the reality of $130 a barrel oil and $4 gas.

Wagoner told investors at the company's annual shareholder meeting in Delaware that the plant closures will affect factories in Moraine, Ohio, Janesville Wis. as well as plants in Oshawa, Ontario and Tolucua, Mexico. All four factories assemble trucks and SUVs.

"Since the first of this year, however, U.S. economic and market conditions have become significantly more difficult," he said. "Higher gasoline prices are changing consumer behavior, and they are significantly affecting the U.S. auto industry sales mix."

The Moraine plant employs 2,500 people, while the Janesville plant employs 2,600 people. Both factories employed thousand of additional workers years ago when demand for SUVs and trucks were higher. The Mexico and Ontario-based plants employ 2,500 factory workers each as well.

The Moraine plant, which produces the Chevrolet TrailBlazer, GMC Envoy and Saab 9-7x, will be shut down by 2010, GM said. The Janesville plant will stop production in 2010 of the Tahoe, Suburban and Yukon models, or possibly sooner. 

In Canada, the Ontario-based plant will shut down in 2009. That plant produces the Chevy Silverado and GMC Sierra. The Mexico plant, which makes the Chevrolet Kodia will shut down by the end of this year.

Wagoner said GM has no plans to produce anything at the four closing plants in the future.

In addition to shutting down these four factories, Wagoner told shareholders that GM is considering "all options" for company's heavy-duty Hummer brand, including possible revamp of the whole brand, or even a possible sale.

Like SUVs and trucks, the Hummer brand has suffered significantly under the weight of high gasoline prices. The brand was almost 60% of GM's profit at the beginning of the decade, according to various news reports, but demand has collapsed as consumers have found little need to buy mammoth fuel-inefficient vehicles.

In order to compensate with a change in demand for trucks and SUVs, GM announced today that it would focus almost solely on producing cars or crossover vehicles for the upcoming years. Eighteen of the next 19 GM models the company will announce in the coming years will be cars or crossovers, and more than 20 models with have fuel hybrid options.

To increase production of small-sized cars, GM will construct a new plant in Lordstown, Ohio, to produce the Chevy Aveo.

Also, GM said its Board of Directors has approved the production and sale of the all-electric Chevrolet Volt car by 2010. This would be GM’s second major offering for an all-electric vehicle, after the EV1 in the 1990s. The Volt will be made in Detroit.

"While some of the actions, especially the capacity reductions, are very difficult, they are necessary to adjust to changing market and economic conditions and  to keep GM's U.S. turnaround on track and moving forward," Wagoner said.

GM shares rose 36 cents, or 2.1 percent, to $17.80 in pre-market trading.