UYUNI, Bolivia  In the rush to build the next generation of hybrid or electric cars, a sobering fact confronts both automakers and governments seeking to lower their reliance on foreign oil: almost half of the world’s lithium, the mineral needed to power the vehicles, is found here in Bolivia  a country that may not be willing to surrender it so easily.

Japanese and European companies are busily trying to strike deals to tap the resource, but a nationalist sentiment about the lithium is building quickly in the government of President Evo Morales, an ardent critic of the United States who has already nationalized Bolivia’s oil and natural gas industries.

For now, the government talks of closely controlling the lithium and keeping foreigners at bay. Adding to the pressure, indigenous groups here in the remote salt desert where the mineral lies are pushing for a share in the eventual bounty.

“We know that Bolivia can become the Saudi Arabia of lithium,” said Francisco Quisbert, 64, the leader of Frutcas, a group of salt gatherers and quinoa farmers on the edge of Salar de Uyuni, the world’s largest salt flat. “We are poor, but we are not stupid peasants. The lithium may be Bolivia’s, but it is also our property.”