Campus threats forced lock-downs and evacuations at universities in Tennessee, Texas and Oklahoma a day after a Virginia Tech student's shooting rampage killed 33 people.

At the University of Tennessee at Chattanooga, officials ordered three campus administration buildings evacuated for almost two hours Tuesday morning in response to a telephone bomb threat. The city's bomb squad searched the buildings but found nothing, campus spokesman Chuck Cantrell said.

Cantrell said there was no reason to believe the bogus threat was related to the shootings at Virginia Tech, but "we just chose to err on the side of caution today."

In Austin, authorities evacuated buildings at St. Edward's University after a threatening note was found, a school official said.

Police secured the campus perimeter and were searching the buildings, St. Edward's University spokeswoman Mischelle Amador said. She declined to say where the note was found and said its contents were "nonspecific."

Students who live on campus were being allowed to return to their dormitories as police finished searching each building, Amador said. Faculty, staff and all other students were asked to stay away from the campus, and morning and afternoon classes were canceled. About 5,200 students are enrolled at the Catholic university south of downtown Austin.

Amador said the university's reaction was not influenced by Monday's attack at Virginia Tech.

"No matter what day or when this would have happened, we will always take the necessary precautions to protect our students, our faculty, our staff, the entire university community," she said.

The lock-down at the University of Oklahoma, had started with a report of a man spotted on campus carrying a suspicious object, officials said.

The man was carrying an umbrella, not a weapon, and he later identified himself to authorities, University of Oklahoma President David Boren said in a statement. Boren initially had said the person was believed to carrying a yoga mat.

"We now consider the matter closed," Boren said. "We always want to err on the side of caution in a situation like this.