A much promoted “massive rally” at the Concord Naval Weapons Station drew only 350 demonstrators and resulted in the arrest of three for trespassing, authorities said. Contra Costa County Sheriff’s Deputy Scott Parsons made the crowd estimate and said the arrests came after some of the demonstrators tried to push open a gate into the weapons station. “The Marines didn’t let them,” Parsons said. “For the most part, the demonstrators stayed well outside the area and spent the day making speeches.” The demonstrators were protesting U.S. involvement in Central America. The station is believed to handle weapons shipped to that region. When the marchers walked through the nearby community of Clyde, about 30 counter-demonstrators protested their presence.