The president of Lincoln University said Thursday that he cannot fire a tenured professor who has questioned the Holocaust and expressed virulent anti-Israel views, because the teacher has kept his opinions out of the classroom.

A statement from Ivory V. Nelson, president of the state-related university in Chester County, said that Kaukab Siddique's beliefs may be "insidious" but that he could express them "as long as he does not present such opinions as the views of the university."

"Dr. Siddique has made it apparent that his opinions are his own and are not a part of his curriculum," Nelson said.

Siddique questioned the Holocaust and called for the destruction of Israel in forums including a September rally in Washington and an online magazine he edits called New Trend.

After video of the rally was posted last week, Siddique told The Inquirer that he was against Israel but not against Jews. On Tuesday, Siddique told the online news site InsideHigherEd.com that his remarks should be put in the context of academic freedom.

"That's freedom of expression going up the smokestack here," Siddique said. "I'm not an expert on the Holocaust. If I deny or support it, it doesn't mean anything."

The statement from Nelson came two days after Joseph Torsella, chairman of the Pennsylvania State Board of Education, questioned whether Siddique was fit to teach and whether school resources had been used to spread anti-Semitism on campus.

"Academic freedom and the system of tenure designed to protect it are critical elements of higher education," Torsella wrote to Nelson on Tuesday. "Denying the Holocaust - a tragic historical fact - is another matter entirely."

On Thursday, Nelson called the Holocaust "a well-documented historical fact" and said the university did not condone incitement to destroy any people or nation.

Siddique's "latest activities, like his earlier writings and statements, are an insult to all decent people," Nelson said.

But, he continued, "we cannot take action at this time based on the content of Dr. Siddique's statements and opinions - no matter how insidious they may be - without undermining the principles on which Lincoln University was founded."

Siddique, who was hired in 1985, is a tenured professor in the English and mass communications department. This semester, he is teaching a pair of English composition classes, and courses on world literature and literary criticism, according to university officials.

He did not immediately respond to a phone call and e-mail from the Associated Press.