Two US universities on Friday asked all employees and students to leave their campuses after the institutes received separate bomb threats, Xinhua reported.
The North Dakota State University in Fargo posted a statement on its website, and sent an emergency message to students around 9.50am, ordering all employees and students to leave campus by 10.15am.
"This includes residence hall students, who, if necessary, should walk to locations off campus. This also includes the downtown buildings and agricultural facilities," Xinhua quoted the statement as saying.
The statement said a bomb threat prompted the evacuation order, but gave no further details. More than 14,000 students are enrolled at the university.
The University of Texas in Austin also ordered an evacuation around 10am after a man claiming to be affiliated with the Al Qaeda called in a bomb threat, according to university officials.
"Immediately evacuate all buildings and get as far away as possible. More information to come," said an alert posted online and sent to students.
"We received a bomb threat this morning (Friday) from a man claiming to be part of Al Qaeda," university spokesman Gary Susswein was quoted as saying.
ABC News said a warning call came in shortly after 8.30am, with a man saying there were bombs on campus that would go off within 90 minutes, police said.
"Out of an abundance of caution, we're evacuating all buildings, making sure all buildings are secure," the university spokesman said.
It was not known if the two bomb threats were related.