BERKELEY, Calif. – Protests against deep education cuts at universities turned violent as demonstrators threw punches and ice chunks in Wisconsin and blocked freeways and smashed car windows in California.

RANDALL BENTON/The Associated Press

Sheriff's deputies carried away University of California-Davis student Laura Mitchell during a demonstration at the campus on Thursday.

At least 15 protesters were arrested by University of Wisconsin-Milwaukee police after as many as 150 students gathered at the student union then moved to an administrative building to deliver petitions to the school chancellor.

Later in the day, a major San Francisco Bay area freeway was shut down in both directions by college students protesting budget cuts at California campuses.

About 150 people who were part of a much larger group demonstrating in downtown Oakland clambered onto the Interstate 880 freeway at the beginning of the evening rush hour Thursday.

The protests were among dozens nationwide in what was billed as the March 4th National Day of Action for Public Education.

Organizers said hundreds of thousands of students, teachers and parents were expected to participate in the nationwide demonstrations.

The steep economic downturn has forced states to slash funding to K-12 schools, community colleges and universities to cope with plummeting tax revenue.

Experts said schools and colleges could face more severe financial trouble over the next few years as they drain federal stimulus money that temporarily prevented widespread layoffs and classroom cuts.

Some university officials said they supported the protests as long as they remained peaceful.

"My heart and my support are with everybody and anybody who wants to stand up for public education," University of California President Mark Yudof said in a statement. "Public education drives a society's ability to progress and to prosper."

Terence Chea,

The Associated Press