Officials with the Sheriff’s Office said they received the first call at 12:19 p.m. They said they did not know what the dispute was about. No arrests were made, but the authorities detained and were questioning the two men they believed were involved in the argument. Both of the men were hospitalized with injuries and were described as persons of interest by the authorities. One of the men had student identification, but officials had not confirmed that he was enrolled at the college.

An official with the Sheriff’s Office, Maj. Armando Tello, said there appeared to be only one gun involved. Major Tello was the acting sheriff because Sheriff Adrian Garcia was out of town.

The shooting shocked students, faculty members and administrators at the 200-acre campus. The school is in northern Harris County and about 30 minutes from downtown. It is so close to George Bush Intercontinental Airport that college officials said one can often look up and wave at the passengers.

Students said they did not realize that the shots were actually gunfire. Because the shooting occurred outdoors — in a center courtyard near the library and academic buildings, officials said — many heard the sounds. One student sitting at a table on the third floor of the library thought it was a book cart toppling.

“Later we heard people screaming, and we knew it was gunshots,” said the student, Jonathan Moreno, 19, a freshman.