The activists led a rally Friday night outside the San Diego trolley office in East Village. They said the border patrol and Transportation Security Administration unfairly questioned and detained 21 people at the Old Town trolley stop Friday.
Three minors in the group were deported to Mexico.
The protesters said the agencies conducted racial profiling. A border patrol spokesman said the agency does not conduct raids and denies charges of racial profiling.
The spokesman added that this was a case of border patrol assisting the TSA in a routine operation.