Three members of the University of the District of Columbia Board of Trustees resigned yesterday, and sources said Chairman Nira Hardon Long agreed to step down contingent on receiving assurances that she would not be held liable in any civil lawsuit against the university.

The resignations raised hopes that a week-long standoff between students occupying a campus building and administrators is near an end, but the Rev. A. Knighton Stanley, one of those who resigned, said last night that the trustees have made their final offer to students and that they would suspend negotiations until this morning.

"The ball is in their court," Stanley said of student negotiators, who showed signs yesterday of fatigue from their long nights at the bargaining table.

Meanwhile, a key demand by the several hundred protesting students resolved itself when artist Judy Chicago announced in a statement that she was withdrawing the offer of her controversial artwork, "The Dinner Party," as a show of support for "the students' right to determine their own destiny."

Long's resignation has been a key demand of student demonstrators staging a strike since last Wednesday. Last Friday, Long had said she would leave the chairman's position, but not the board, effective Oct. 16.

The students said that was not enough, and vowed that classes at the city-run university would be shut down until all trustees appointed by Mayor Marion Barry -- including Long and Stanley -- resigned.

The strike, now in its seventh day, is the latest crisis to hit the beleaguered 13-year-old institution, which has a student enrollment of 12,000 and has repeatedly faced demoralizing changes in leadership.

Eight or nine members of the 15-member board have been negotiating almost around the clock with the student protesters since Saturday. The trustees have agreed to many of the 43 student demands, and said they would consider others.

But the board members remained adamant that they would not step down, saying a mass departure of leadership could jeopardize the school's accreditation and set a bad precedent for other city agencies under fire.

Some trustees have resisted leaving to avoid being blamed for the institution's troubles.

Sources said that Long had been prepared since late last week to step down from the board, but was concerned about the possibility of being held liable in a lawsuit filed against the trustees by Rafael L. Cortada, who was fired as president in May.

University officials yesterday were trying to work out details of Long's legal protection, sources said.

"We believe that resignations from the board is a matter of individual conscience and individual responsibility," Stanley said.

Besides Stanley, trustees who resigned yesterday are Alonza T. Evans and Joseph Webb, who were elected to the board by alumni. It is unclear what effect the resignations would have on the negotiations, which were reported most of yesterday to be in a delicate phase.

Protesters had not sought the resignations of Evans and Webb, but they have fought strenuously for the resignations of trustees appointed by Barry. Students focused much of their anger on Long, who has not appeared on campus since the strike started last week. In her absence, Stanley emerged as a leading trustee.

Stanley's resignation is effective next March 31. Long could not be reached for comment yesterday.

Arthur M. Reynolds, another Barry appointee, resigned Friday but it was unclear why.

Student leaders said that Herbert O. Reid Sr., another Barry appointee, resigned on Monday for health reasons. Another Barry trustee, Lourdes Miranda, had stepped down in late August, but it was not announced until recently.

"I resigned because I wanted to make a move that other trustees would follow," said Webb. "All the students are asking is an opportunity to evaluate their trustees. If I do not serve them well, then let them accept my resignation."

The board agreed on Sunday to reexamine its aquisition of Chicago's "Dinner Party," considered obscene by some critics. But the trustees expressed concern that they were contractually obligated to accept the gift. The city had planned to place the work in the university's Mount Vernon Library building downtown, and to raise $1.6 million in bond money to renovate the structure. The protesters wanted city money spent on educational programs, not the art space.

"It is clear that the students have a valid set of demands that will promote their own growth and the needs of the university," Chicago said in her statement. She expressed hope that once the students and administration resolve their differences, they again would consider accepting her artwork.

But she said it appears that the school's financial crunch violates her "threshold condition" for the gift: money to permanently house the artwork.

Rep. Stan Parris (R-Va.), who sponsored an amendment to the D.C. appropriations bill that withheld the $1.6 million needed to house the work, congratulated the students last night on their victory.

"My effort was never aimed at reducing funds to be used for education, but to bring attention to just how far out of line the priorities of the board of trustees had become," Parris said in a statement.

Yesterday's developments came as protesters persuaded most students to honor a class boycott for the second day this week, in defiance of an administration attempt to resume classes.

As on Monday, student demonstrators yesterday left the administration building they were occupying to stand in front of other campus building entrances and near the Van Ness Metro station.

While some students said yesterday's boycott of classes seemed even more effective than Monday's, they also expressed concern that the standoff was dragging on for too long.

"I believe they should start compromising," said Shannon Onley, 20, who was one of the few to attend classes yesterday. Although she agreed with the students' demands, she said they should not expect all of their demands to be met.

Teachers, who have generally supported the strike, are also expressing concern that the standoff is taking so long, especially because midterm examinations are scheduled to begin next week.

The demonstrators' fatigue was evident in the haggard looks of hoarse-voiced Mark Thompson, the student leader.

"We need a victory," Thompson said during a morning news conference after having been in negotiating sessions for 20 of the previous 24 hours, "so that never again will anyone be able to say anything negative about a student at UDC."

Staff writer Keith Harriston contributed to this report.