SAN DIEGO -- Hundreds of shouting and chanting demonstrators marched along downtown streets Wednesday evening, part of an antiwar rally that quickly left several participants under arrest, authorities said.

The protest on Broadway and surrounding roads in central San Diego began in earnest around 5 p.m., the deadline for President George W. Bush's call for Saddam Hussein to go into exile with his sons or face a U.S.-led military assault.

The first shots of the war were fired about 90 minutes later, as San Diego Police Department officers in riot gear had taken at least two demonstrators into custody, a dispatcher said. It was not immediately clear what led to their arrests, he added.