A university building has been locked down due to an occupation by a pro-Palestinian protest group.
Oxford Action for Palestine (OA4P) organised a sit-in at the University of Oxford offices on Wellington Square.
The group is demanding a meeting with the university to review its policies relating to the Israel-Gaza conflict.
Large numbers of police are at the scene.
BBC Radio Oxford reporter Phil Mercer-Kelly, who is at the scene, hundreds of people were outside the building, being prevented by police from entering.
He added there had been a "big movement" as police forced a group of people back to Little Clarendon Street to allow police vans to leave.
Some protesters are inside the building and a Palestinian flag has been hung out of one window, alongside a list of demands.
A spokesperson for OX4P said: "Today, Oxford students staged a peaceful sit-in to demand that the university meet with us after two weeks of non-response.
"Instead of engaging in dialogue with her students, the vice chancellor chose to evacuate the building, place it on lockdown, and call the police to make arrests.
"We demand the administration meet with us to negotiate immediately."
The university has yet to respond to a request for comment.
Thames Valley Police has also been contacted by the BBC for a response.
On 6 May, so-called "liberated zones" were set up at Oxford's Museum of Natural History and King's College, Cambridge.
The demonstrators called for the universities to cut financial ties with Israel following its offensive in Gaza.
More than 33,000 people have been killed in Israel's offensive in Gaza, the Hamas-run health ministry there says, the majority of them civilians.
Israel rejects accusations that it is engaging in genocidal acts in its campaign in Gaza, and has insisted it has the right to defend itself following the armed incursion by Hamas on 7 October.