BUENOS AIRES, Argentina (AP) — Aymara Indians are vowing to block Dakar Rally competitors from Bolivia's high-altitude salt flats, where President Evo Morales is hoping the world's hardest rally will boost tourism.

Organizers of the race, which starts in Rosario on Sunday, are permitting only motorbikes and quad bikes near Salar de Uyuni, the largest salt flats in the world. Cars and trucks will take a more direct route from Argentina into Chile on Jan. 12 and 13.

While some Aymara back the race, others fear crowds will leave rubbish and the racers will carve deep marks into the shiny white surface.

Morales, an Aymara, wants the brief Bolivia leg to bring attention to one of the world's most remote and beautiful places.

The Salar de Uyuni is 11,800 feet (3,600 meters) above sea level and stretches over more than 4,000 square miles (11,000 square kilometers). It's a breeding ground every November for South American flamingos, and the briny water under the lake's hard surface has high concentrations of lithium, which is mined for batteries.

Rain is expected during the Bolivia leg, which could leave a sheen of water over the crusty surface and create what seems like an endless mirror. But that liquid also could moisten the salt, raising chances that heavy equipment will break through hard layers that have built up over thousands of years.

Cars commonly cross the salt flats, with SUVs carrying tourists and pickups supplying salt harvesters and lithium operations. But they generally avoid the lake when it's covered with water, which is why racing cars and trucks will detour.

"It's a precipitous route, there could be water on the surface of the salar, and there's only one lane for all the vehicles, which doesn't allow for cars and trucks," Dakar Rally chief Etienne Lavigne said on the race website.

The organizers did not respond to requests for comment on Thursday on the environmental issues.

Bolivia's environment and water minister, Jose Zamora, said his agency was preparing an environmental permit and will protect the area's natural beauty. Meanwhile, the government also was sending troops to keep close watch over the race.

A total of 438 drivers from 52 nations are competing in the rally, which covers about 5,600 miles (9,000 kilometers), crossing the Andes and Atacama Desert before finishing in Valparaiso, Chile, on Jan. 18.

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Associated Press writer Paola Flores in La Paz, Bolivia, contributed.