Several thousand people were evacuated from Robert F. Kennedy Memorial Stadium yesterday after authorities received a bomb threat during a band competition, officials said. The stadium was searched, but no bomb was found.

D.C. police said that everyone was ordered to leave the Battle of the Bands competition after a telephoned bomb threat was received about 5 p.m.

The evacuation appeared to be one of the largest in the Washington area during the period of heightened security alertness that has followed the Sept. 11, 2001, terrorist attacks.

Mark H. Tuohey III, director of the D.C. Sports and Entertainment Commission, which runs the stadium, said two calls were received shortly after the concert began, saying that there was to be "some kind of bomb detonation" inside the facility. The calls, he said, were "apparently traced to people inside" RFK.

Tuohey said stadium authorities and police decided it would be "too risky" to search with the crowd inside.

"You don't take those chances with that many people," he said.

Tuohey said officials are to discuss today whether to reschedule the event.

Witnesses said most of the bands -- totaling about 15 school and college marching units from the District and Maryland -- had yet to perform when a public address announcement ordered the evacuation.

Resplendent in brightly colored uniforms, carrying flags and banners and gleaming brass instruments, band members joined spectators in reactions that included dejection, resignation and bewilderment.

"This is crazy," said spectator Marjorie Gleaton, 40, of Northeast Washington as she waited for a Metrobus to take her home.

"People are just trying to have a good time," she said of the crowd.

Herman Snyder of Fort Washington, whose daughter Mercedes plays flute in the Friendly High School band, said spectators were not told why they had to leave.

"They didn't give us any explanation -- just to get out," he said. According to witnesses, news of the threat came only by word of mouth and from encounters with arriving police officers.

Friendly's band had played, Snyder said, but the competition, which was scheduled to start at 4 p.m., was far from over. "There was a lot more to go," he said. "I didn't get my money's worth."

It was not immediately possible to reach sponsors of the event. One posting on the Internet indicated that tickets were $15.

"I want my money back," said Nae Brown, 14.

She was one of many who described the cancellation as a letdown on a pleasant afternoon and evening, with Washington reveling in fine weather.

"I was grooving, and everyone was having a great time," she said.

Even though the band from the District's Hine Junior High School did get to perform, members were left unhappy, said Ed Anderson, the school's director of bands.

One reason for participating is to assess and enjoy the achievements of other groups. The Hine unit "didn't get to see the others perform," Anderson said. "It's a disappointment."

But some people made the best of the situation.

Rather than pack up immediately, some bands remained outside in a parking area, giving impromptu performances.

Renard James, 25, a drum major with the Morgan State University band, took in the informal concert.

"Sometimes you go to work and you can't do the job you're supposed to do," he said. "That's the way it is."

One man apparently saw a sinister plot at work. Bernard Irving, 23, of Northeast Washington scrawled "Why" on a piece of cardboard and held it aloft.

He said he doubted that there was a bomb scare. What prompted the evacuation, he said, was the unity shown by the spectators. "They," he said in an apparent reference to governmental authorities, "don't want us to be together. We can't have anything going on in our community. They have to shut it down."

Staff writer Katherine Shaver contributed to this report.

D.C. police officer Joshua Strassman directs Battle of the Bands participants and spectators from RFK Stadium.