AUSTIN, Texas - (AP) - Tens of thousands of people streamed off university campuses in Texas and North Dakota on Friday after telephoned bomb threats prompted officials to warn students and faculty to get away as quickly as possible. Both campuses eventually were deemed safe and reopened by early afternoon, as authorities worked to determine whether the threats were related. The University of Texas received a call about 8:35 a.m. from a man claiming to be with al-Qaida who said he had placed bombs all over the 50,000-student Austin campus, according to University of Texas spokeswoman Rhonda Weldon. He claimed the bombs would go off in 90 minutes and all buildings were evacuated at 9:50 a.m. as a precaution, Weldon said. The deadline passed without incident, and the university reopened all buildings by noon. Classes were canceled for the rest of the day, but other university activities were to resume by 5 p.m. North Dakota State University President Dean Bresciani said 20,000 people also were evacuated from his school's main and downtown campuses in Fargo after the school received its threat. FBI spokesman Kyle Loven said a call that included a "threat of an explosive device" came in about 9:45 a.m., but he declined to give further details. He said the agency was trying to determine if the two campus threats were related. NDSU buildings reopened about 1 p.m. and classes were set to resume an hour later, said Bresciani, adding that the campus had been "deemed safe." In Texas, campus sirens wailed and cellphones pinged with text messages when the initial alert when out. Students described more confusion than panic as they exited the sprawling campus in what one described as an "orderly but tense" manner. Students said they were directed off campus by university staff. Also Friday, Valparaiso University in Indiana increased security and posted a warning to students on its website after a vague threat was discovered scrawled in some graffiti. The school says the threat claimed "dangerous and criminal activity" would occur Friday during the university's daily chapel break. The FBI and local authorities searched the campus but found nothing suspicious and university spokeswoman Nicole Niemi said classes and other regular activities were continuing as planned.