BERKELEY, Calif. — The University of California, Berkeley, said Thursday that it would permit the conservative author Ann Coulter to speak on campus in early May, just one day after it canceled her appearance that had been scheduled for next week.

But Ms. Coulter rejected the university’s offer, saying it came with “burdensome” conditions, and insisted that she would show up and speak as originally scheduled next Thursday.

And late Thursday night, a lawyer for the Berkeley College Republicans, which invited Ms. Coulter to campus, threatened to sue the university unless it permits the speech to go ahead.

At a news conference on Thursday, Nicholas B. Dirks, the chancellor, said Berkeley had canceled that event because the police had “very specific intelligence” of threats “that could pose a grave danger to the speaker” and others if it had allowed Ms. Coulter to appear next Thursday. Some recent speeches at Berkeley and other colleges have attracted violent protests.