"They allowed a criminal to leave the scene without taking action," said Michael Wildes, a New York City-based lawyer, who is representing Daniel Vessal, 21, of Philadelphia, the student who said he was struck.
Temple's investigation will determine whether the incident will be considered a hate crime, said spokesman Ray Betzner.
"We're hoping to talk to the individual who was struck," Betzner said, but the student indicated he would not speak with the university until his lawyer is present.
Vessal is the former vice president of Temple's Alpha Epsilon Pi, a Jewish fraternity, according to his Facebook page. His hometown is Philadelphia.
The student group involved, Students for Justice in Palestine, released a statement acknowledging that an "acquaintance" of the group - though not a member - slapped Vessal. The group said Vessal was slapped after he called the all-female members manning the table "terrorists" and said "I can't believe this exists."
According to the statement, Vessal repeatedly approached the table even after the women asked him to leave. The group denied using anti-Semitic slurs. The statement did not identify the man who hit Vessal.
Vessal referred requests for comment to Wildes, a former federal prosecutor in New York and former mayor of Englewood, N.J.
"We're very concerned for his safety," Wildes said of his client. The assault, he said, was "uncalled for, unprovoked and unacceptable" and could have a "chilling effect" on other college campuses if people think they can get away with attacks.
Harassment, bullying and verbal altercations between pro-Palestinian and pro-Israeli students are on the rise on campuses nationally, but rarely have involved physical violence, said Tammi Rossman-Benjamin, co-founder of Amcha Initiative, a California non-profit that combats anti-Semitism on campus.
"We know of lots of very aggressive . . . attempts to really promote an anti-Israel agenda that is not only anti-Israel but is anti-anyone who supports Israel," she said.
Ibrahim Hooper, a spokesman for the Council on American-Islamic Relations (CAIR), a Muslim civil rights and advocacy organization, also acknowledged rising tensions on campuses and in communities.
"It's an unfortunate byproduct of a conflict that has gone on too long and should be stopped immediately," he said. "But no overseas conflict can justify any form of anti-Semitism or intolerant action or speech."
In July, Hooper complained to Temple about another incident: a university police dispatcher wrote to him advocating violence in the wake of the beating of a Palestinian-American boy from Tampa at the hands of Israeli soldiers.
The dispatcher, in an email to Hooper, said the boy was a terrorist who should get: "Two shots to the chest followed my [sic] one to the head to eliminate them as quickly and as efficiently as possible and improve the gene pool!"
Charles Leone, Temple's executive director of public safety, told Hooper the dispatcher had been dealt "severe discipline."
The Anti-Defamation League in Philadelphia on Thursday said it was "shocked and deeply troubled" by reports of the attack on Vessal. But the incident also garnered attention much farther away.
"We are calling upon the city of Philadelphia and the university president to investigate this as a hate crime," said Aron Hier, director of campus outreach for the Los Angeles-based Simon Wiesenthal Center, a Jewish human rights organization.
The university also should look at shutting down the group if it is confirmed that members used anti-Semitic slurs, he said.
Betzner confirmed that university police have not made any arrests. Temple continues to investigate and has briefed city detectives, he said.
University police, he said, offered Vessal medical attention, but he refused. Hier said Vessal was punched and later went to the hospital. Wildes, Vessal's attorney, declined to discuss any possible injuries.
The university is asking anyone with information to contact Campus Safety Services at 215-204-1234.
University officials said they reached out to leaders of Temple's Jewish and pro-Palestinian communities to discuss the incident.