SHASTA LAKE, California — As darkness fell across the crescent-shaped Shasta Dam, eight barefoot Winnemem Wintu warriors armed with bows began the tribe's first war dance since 1887.

Members of the tiny American Indian tribe began the four-day protest Sunday night to stop a potential expansion of the Shasta Dam, which would destroy sacred sites that had survived its original construction.

"The war dance itself is a message, a message to the world that we can't stand to put up with this again," said Caleen Sisk-Franco, the chief who says she received the protest vision from the spirits of ancestors. "We've already lost too many sacred sites to the lake. To lose more is like cutting the legs off all the tribal members."

For more than 20 years, there's been talk of raising the 602-foot high dam that holds back three rivers, including the Sacramento, the state's biggest. Multimillion-dollar studies are underway over the possibility of raising it as little as 6.5 feet and as much as 200 feet, and the Winnemem feel an imminent threat to their way of life.

Three-quarters of the state's rain falls north of Sacramento, and Shasta Lake, with its 370-mile shore, is the largest catch basin. Electricity is produced as waters spill toward the Sacramento River, the water conduit for 22 million people and thousands of farms, said Jeff McCracken of the U.S. Bureau of Reclamation. The bureau operates Shasta Dam, located about 110 miles south of the Oregon border.

But as the state grows by 5 million people each decade and copes with water shortages, officials said they need more water. Of the potential choices, McCracken said, expanding Shasta is one of the most promising.

Expanding the dam could help troubled salmon by ensuring steadier flows in the Sacramento River and keeping temperatures colder for fish as they head from the sea to their birthplaces to spawn, according to Bureau of Reclamation officials.

But Craig Tucker, of the environmental group Friends of the River, said a bigger dam would further inundate the Sacramento, McCloud, and Pit rivers upstream, jeopardizing world-class trout fishing and whitewater recreation.

"Their goal isn't to help the fishery," Tucker said of the dam supporters. "Their goal is to hoard more and more water."

The Winnemem Wintu population has dwindled to 125 members due to a combination of disease, disputes, and departures by members who have abandoned the culture. The tribe last held a war dance in 1887 to protest a McCloud River hatchery that captured the salmon it relied on for its way of life.

About 60 years ago, the tribe relocated the graves of 183 ancestors and abandoned many sacred sites as Shasta Lake swallowed its villages and ancient cemeteries. The tribe said it was promised land elsewhere in exchange, but the only plots received were in a cemetery below the dam.

Sisk-Franco has likened the dam expansion to flooding the Vatican. His tribe is one of hundreds nationwide that are not officially recognized, which limits its clout while negotiating with the government.

If the dam is raised, the tribe said it will forever lose Puberty Rock, where ceremonies are held for girls coming of age. Children's Rock, where young ones seek blessings and the gift of talents, would also disappear. One hundred fifty years ago, settlers killed 42 tribe members in what is known as the massacre at Kaibai Creek, and the site also would be washed away.

"When those places get threatened or occupied or expropriated or somehow taken from them, that calls for preparation for conflict," said Les Field, a University of New Mexico anthropologist.

Chanting and letting out cries, warriors held out bows and arrows in their left hands, the only obvious gesture of war, as they danced around the blazing fire with the dimly lit dam in the distance.