Gregory Porter, 19, of Glenside, Pa., a sophomore majoring in international area studies, was studying abroad at The American University in Cairo when he was arrested, according to school officials.
An Egyptian official said the three were arrested on the roof of a university building near Tahrir Square and had been throwing firebombs at security forces. The official spoke on condition of anonymity because there was no authorization to speak to the media. The U.S. Department of State said it was aware of the detentions of three U.S. citizens in connection with the Tahrir Square protests.
Tens of thousands of people filled the square Tuesday to intensify pressure on Egypt's military leaders to hand over power to a civilian government, part of a wave of protests and violence across Egypt that began Saturday has left 29 dead and thrown the country's politics into chaos less than a week before landmark parliamentary elections were to begin.
Porter is a 2010 graduate of La Salle College High School.
School President Brother Richard Kestler says it was a shock to everyone to learn that Porter had been arrested in Egypt.
"I came back from a prayer service at the school. When I came out I saw this information on my desk. We were all really shocked," Kestler said.
Brother Kestler says that doesn't appear to be the young man he knew here at La Salle.
"While he was in school here, he was just an outstanding student, very good guy. He worked with our speech and debate program. As a matter of fact, he received a national recognition where he came seventh in his policy address that he gave there," Kestler said.
Drexel University officials said they were working to have Porter returned home safely.
"Drexel administrators are in contact with Porter's parents and are working with authorities at The American University in Cairo and the U.S. Embassy to have Porter released and returned home safely," Drexel spokeswoman Niki Gianakaris said in a statement.
Action News spoke with Porter's father and his older sister, who is also a student at Drexel; both say they have no comment until they learn more about Greg's predicament.
Morgan Roth, a spokeswoman for The American University in Cairo, said the school was working to get answers about the whereabouts of Porter and the other two students - whom she identified as Luke Gates, a 21-year-old Indiana University student from Bloomington, Ind., and Derrik Sweeney, a 19-year-old Georgetown University student from Jefferson City, Mo.
"We're working very closely with the embassy to try to ascertain where they are," Roth said.
Morgan Roth says the three were supposed to be questioned Tuesday under the observation of university and U.S. Embassy representatives. She thought that was cancelled but later found out they had been questioned with an embassy official present.
The Associated Press contributed to this report.