NEW HAVEN, Conn. (AP) — As a union push stalls at Yale University, organizers are stepping up pressure to bring the administration to the negotiating table, including a vow by some graduate students to go on a hunger strike until talks begin.

Graduate assistants in eight departments at the Ivy League school voted in February to unionize, and they appeared to be on track to become among the first to do so since the National Labor Relations Board ruled last year that those assisting in teaching and research at private universities have a right to union representation.

But Yale is challenging the union strategy of voting by individual departments, as opposed to the graduate school as a whole, and has said the requests by Local 33-UNITE HERE for collective bargaining are premature.

Hundreds of graduate students and their supporters participated in a march Tuesday evening to the home of Yale's president, Peter Salovey, and demonstrators announced that eight graduate students would begin a fast.

"I've been waiting for Yale to negotiate for four years. That doesn't seem to matter to them," said Aaron Greenberg, a union chairman who is among the hunger strikers.

Graduate assistants at public universities have been able to organize for years, but until a reversal last August by the NLRB, graduate students at private schools could not be considered employees. Union organizers at Yale said they suspect university officials are dragging the process out because they believe the NLRB will become more sympathetic to their view under President Donald Trump.

School officials said the fast is unwarranted, and Salovey said in a written statement that the students should reconsider and avoid actions that harm their health.

The Yale organizers say they believe a union would help address concerns surrounding pay and benefits.

Yale says it provides "unsurpassed" support for doctoral students. In a statement Monday, it said it has challenges pending regarding an NLRB regional director's finding that teaching fellows are employees and regarding the union's strategy of focusing on individual, hand-picked departments.

"That strategy is unprecedented in higher education," the university said. "Unions that have organized at other private universities, including Columbia, Harvard, Duke and Cornell, have all sought school-wide bargaining units — not the separate departmental units advocated by Local 33 at Yale."