BERKELEY, Calif. — Days after the University of California, Berkeley, canceled an appearance by the author Ann Coulter, two conservative organizations filed a federal lawsuit on Monday accusing the university of trying to “to restrict conservative speech” on campus.

The legal action comes after the university had canceled Ms. Coulter’s appearance, scheduled for this week, on the grounds that specific threats by anarchist groups threatened security on campus. The groups that invited Ms. Coulter say she is planning to come anyway.

The lawsuit, filed in Federal District Court in San Francisco, was brought by the Berkeley College Republicans and the Young America’s Foundation, a national organization that promotes conservative causes.

“Berkeley promises its students an environment that promotes free debate and the free exchange of ideas,” the lawsuit said, but the promise was breached “through the repressive actions of university administrators and campus police.”

Berkeley has become a meeting ground of activist and militant groups from the left and right in recent months, leading to violent clashes that left some people injured.

The lawsuit demands that the Berkeley College Republicans be allowed to “bring speakers of its choosing to speak on campus.” It also says the College Republicans and the Young America’s Foundation are entitled to unspecified “monetary damages arising from the unconstitutional actions” of university administrators, as well as legal costs.

A university spokesman said the issue was a matter of security.

“Ann Coulter is welcome on this campus but at a time when we can provide a venue that law enforcement professionals believe to be protectable,” a spokesman for the university, Dan Mogulof, said.

Last week the University proposed an alternative date and time — May 2, in the afternoon — an offer that the College Republicans rejected because it came during a study week before the end of the term.

Mr. Mogulof said the university had received “letters and threats” from around the country.

“As individuals or part of a militia, they intend to come to the campus to support Ann Coulter,” he said. “Our concerns have only grown.”

In addition to accusing the university of “unilaterally” canceling Ms. Coulter’s speech, the lawsuit says the Berkeley College Republicans were forced to cancel a speaking engagement earlier this month by David Horowitz, another conservative writer, after the university demanded that the speech take place in the afternoon and a mile away from the center of the campus.

The lawsuit accuses the university of unreasonably restricting the time and place of events involving high-profile speakers which resulted in the “marginalization of the expression of conservative viewpoints.”