An unidentified man is led away from the Graduate Students' Union building in downtown Toronto on Sunday morning during a mass arrest. (CBC)

A police raid that rounded up about 70 people on Sunday morning was an attack on freedom of speech, says the University of Toronto group that billeted the protesters.

Members of the executive of the University of Toronto Graduate Students' Union issued a news release Monday defending their decision to provide accommodation to G20 protesters who were later arrested by police.

The roughly 70 people were arrested at the GSU building, near Spadina Avenue and College Street, on Sunday morning when police swooped in. Many of them were sleeping when officers woke them.

At the time, police said those arrested "were found in possession of bricks and other items that could compromise the safety of the citizens of Toronto."

Police spokesman Const. Rob McDonald described the items as "street-type weaponry."

There have been suggestions that some of those taken into custody may have been members of a Black Bloc-type group, which is alleged to have caused property damage in some parts of Toronto during Saturday's protests.

The GSU said in its release that it provided "legal" accommodation to people wanting to "exercise their democratic right to participate in a legal protest."

"The student movement has a long and honourable tradition of supporting legitimate, constitutionally guaranteed rights and freedoms, including the right to free assembly, free speech and peaceful protest. The GSU appeals to all members of the Canadian public to help us protect those rights."

The university closed its entire downtown campus during the G20, but the GSU allowed access to its building.

"As a matter of course, the GSU has billeted individuals in the past for many events, as have other student unions and universities. The University of Toronto was aware of our plans to remain open," the statement said.

Two members of the GSU executive committee were also taken into custody. They have not yet been released.

"The GSU categorically denies any involvement in any undemocratic activity and we call on university officials, the public and the media to support our collective freedoms and to release our innocent executive members with appropriate apologies," the GSU said.