VISTA, Calif. -- A peaceful demonstration for rights for illegal immigrants became threatening when about 200 people refused to go home and began throwing rocks and bottles at sheriff's deputies, authorities said today.

There was no clash, but about 75 individuals tried to make a stand at about 10:45 p.m. on Monday at a park on Santa Fe Avenue and West Los Angeles Drive in Vista, according to California Highway Patrol Officer Larry Landeros.

A line of law enforcement officers in riot gear walked toward West Los Angeles Drive, shouting "Go home and disperse. If you do not do so, you will be arrested. The demonstration is over."

Youths walked along the alleys behind Santa Fe Avenue and in the open space areas, whistling and shouting. The officers had dogs with them and a line of patrol cars slowly progressed toward the intersection.

No arrests were made and no shots were fired, according to San Diego County sheriff's Lt. Phil Brust.

About 40 patrol cars from El Cajon, Carlsbad, Oceanside, San Diego, Chula Vista, Escondido and the CHP responded to the disturbance, authorities said.