Protestors stop traffic on pot holiday

A block-long line of protesters has marched onto the University of Colorado, testing the school's determination to push the annual April 20 marijuana celebration off campus.

The protesters waved signs and a few appeared to be smoking marijuana as they entered the campus Friday afternoon. They chanted, "Roll it, smoke it, legalize it." It wasn't immediately clear what police officers planned to do.

The university has spread smelly fertilizer on a popular campus quadrangle where last year's rally attracted more than 10,000 people.

Three people were arrested for trespassing when they walked onto the quad and refused to leave.

Officials also closed the campus to unauthorized visitors and are offering a free campus concert by hip-hop star Wyclef Jean timed to coincide with the traditional 4:20 p.m. pot gathering.

(Copyright 2012 by The Associated Press. All Rights Reserved.)