Two men have been arrested at the University of Nottingham campus under the Terrorism Act, police have said.
Police said the men, aged 30 and 22, were arrested on Wednesday morning. One is reported to be a student and the other a former student.
They are being questioned while premises connected to them, including campus property, are searched.
Police said it was a joint operation between Nottinghamshire Police and the Midlands counter-terrorist unit.
Supt Simon Nickless from Nottinghamshire Police said officers had been working alongside community representatives to "offer support and reassurance".
He said the operation has been "low-key" and the community's response to it had been "calm and rational".
"Feedback is that people accept that this is the sort of operation that is necessary and reasonable for the welfare of communities," he said.
A uniformed presence is in place at the main Trent building, which houses the schools of English, modern languages and philosophy as well as management offices.
Jonathan Ray, a spokesman for the university, said the institution "has been co-operating fully from the outset throughout this inquiry".
"Nottinghamshire Police have stressed that there is no risk to the university community or to the wider public," he said.
"Here, at the institution, we fully accept that this sort of police operation is necessary and reasonable for the welfare of our communities."