By NBC News

Three American students were arrested Monday evening during protests in Tahrir Square, a spokeswoman for The American University in Cairo told NBC News.

Luke Gates, a student at Indiana University from Bloomington, Ind., Gregory Porter, a student at Drexel University from Glenside, Pa., and Derrik Sweeney, a student at Georgetown University from Jefferson City, Mo., are being held at the Abdeen police station in Cairo, reported NBC. 

The three are currently studying abroad at The American University in Cairo. University spokeswoman Morgan Roth said the university is in "fact-finding mode" about the detentions at the moment.

Read more about the events in Egypt

"I don't have specifics on the charges they are facing or if they have been formally charged. I just know that they are being detained," Roth told NBC. The American University is working with the U.S. Embassy in Cairo to monitor the students' well-being, she said.

NBC's Richard Engel said Egyptian television was reporting three American citizens were arrested after being seen throwing fire bombs from the roof of a building belonging to the American University near Tahrir Square, and that the U.S. Embassy was investigating.

The State Department has not yet been able to gain consular access to the students.

The students' parents were notified Tuesday morning of the arrests. Drexel University, Gregory Porter's school, released a statement saying "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."

The two other students' universities have been notified of the arrests as well.

Meanwhile, Egyptians converged on Tahrir Square on Tuesday in response to a call for a so-called "million-man march" as protests against the country's military rulers entered a fourth day. Read full coverage here.