The vast majority of Muslim students attended class at San Jose State on Monday, defying anonymous death threats and expletive-laden hate graffiti on campus, authorities said.
Muslim student leaders said that female students in hijabs, or head scarves, felt particularly vulnerable.
They moved in clusters to class, Muslim student leaders said.
Authorities said they believe the slurs are the work of one individual.
"We're easy targets," said Sameena Usman, 22, a Muslim and political science major specializing in Middle Eastern studies.
"That was the fear we had," she said, "but I wasn't going to let this stop me from going to class. This person did this to make us feel scared."
And for a while Monday, Usman conceded, she was frightened, saying that she mistook a boom from a nearby construction site for a gunshot.
But then the young student said she resolved, "If we let them do that, then they win."
Extra university police officers patrolled the campus of 30,000 students. Muslim students were advised to be watchful. Some failed to attend class, but most defied the threats, said Mohammad Naaman, 21, president of the Muslim Students Assn. They weren't going to let hateful messages intimidate them, he said.
The scrawled threats were discovered on bathroom walls Thursday. Campus police painted over the graffiti, which reappeared Friday. Among the messages was: "Muslims will be shot on San Jose State University campus on March 10th."
"We take this very seriously," said FBI Special Agent LaRae Quy. "We are assisting the San Jose University Police, trying to locate a suspect."
University police were at their highest alert Monday, officials said. By evening, no incidents had occurred.
"We live in this bastion of diversity," said Helal Omeira, executive director of the Northern California Council on American Islamic Relations and a San Jose University student.
"By and large, I think we get along with each other. These isolated incidents of hate," he said, "are very unfortunate. I would argue that they're from a marginalized part of our community."
Since Sept. 11, 2001, Muslim students have been involved in campus teach-ins and discussion groups with the Jewish Student Assn., all without incident.
From its San Francisco office, Karen Zatz, associate director of the Anti-Defamation League, said, "The ADL is extremely concerned over this incident. We deplore threats against individuals based on religion." The organization offered its "concern and support."
In response to the graffiti, Muslim student leaders met with campus officials Friday.
While most of the campus remained unaware of the incident, the group agreed to notify Muslim students.
San Jose State University President Robert L. Caret sent an e-mail warning Muslim students and advising them to avoid unlighted or deserted areas and not to walk alone or to enter elevators with strangers.
The e-mail also told the Muslim students to "be aware of your surroundings" and to call police if they saw anything suspicious.
"We abhor such incidents," Caret wrote.
"They go completely against the tolerance and respect for diversity to which this campus is strongly committed," he added.
By late Monday, Naaman declared, "It's a sad situation" but the overwhelming support he and other Muslim students received from university officials, faculty and fellow students was, he said, "gratifying. I'm very happy with the response."