Students at the University of California at Berkeley who invited conservative commentator Ann Coulter to speak on campus are threatening to sue the university if it does not find a proper time and venue for her to speak next week.

Harmeet Dhillon, who represents the Berkeley College Republicans, said in letters sent Friday to UC Berkeley’s Interim Vice Chancellor Stephen Sutton and chief attorney Christopher Patti that if Coulter is not allowed to give a speech on campus on April 27 she will file a lawsuit in federal court because the university is violating the students’ constitutional right to free speech.

"It is a sad day indeed when the birthplace of the Free Speech Movement, is morphing before our eyes into the cemetery of free speech on college campuses," Dhillon wrote.

School officials told the Berkeley College Republicans on Tuesday, and the nonpartisan Bridge USA which coordinated the event, that it was being cancelled due to security concerns.

Chancellor Nicholas B. Dirks said that police have "very specific intelligence regarding threats that could pose a grave danger to the speaker," her audience and protesters if the event goes ahead next Thursday.

Officials offered an afternoon event on May 2, when they can offer an "appropriate, protectable venue" but Coulter rejected it, saying she is not available that day. She also tweeted, "THERE ARE NO CLASSES AT BERKELEY THE WEEK OF MAY 2." The period is known as Dead Week, when students are studying for final exams.

"You cannot impose arbitrary and harassing restrictions on the exercise of a constitutional right," Coulter told "Hannity" on Thursday night. "None of this has to do with security."

It is the latest skirmish in a free-speech fight involving conservative voices on college campuses across the country, including at Berkeley. In February, masked rioters at the school smashed windows, set fires, and shut down an appearance by former Breitbart News editor Milo Yiannopoulos. Last week, the Berkeley College Republicans said threats of violence forced them to cancel a speech by writer David Horowitz. Writer Charles Murray's appearance at Middlebury saw riots last month, and Heather Mac Donald's speech at Claremont McKenna College was streamed online earlier this month after protesters blocked the door to the venue.

Berkeley has been the site of clashes between far-right and far-left protesters, most recently at a rally last weekend called in support of President Donald Trump in downtown Berkeley.

The Associated Press contributed to this report.