Eighteen protesters were arrested after they sat in the middle of a busy intersection during rush hour, blocking traffic.
Unionized city employees protesting layoffs and wage reductions marched from San Francisco City Hall to Market Street this afternoon.
A circle of demonstrators blocked the intersection of Market and Eighth streets at 6 p.m.
Service Employee International Union Local 1021 officials say the city intends to lay off 500 city public health and school district employees and that the layoffs could be prevented by a budget appropriation to be considered by the Board of Supervisors on Tuesday.
Police arrested 18 people on misdemeanor charges of blocking traffic. The protesters were cited and released, according to police.