Three Concordia University buildings in downtown Montreal that were evacuated after the institution received bomb threats targeting Muslim students were re-opened Wednesday evening.
Classes were disrupted earlier in the day for several hundred students as authorities searched the facilities for explosive devices.
Police ended their sweep in the afternoon, but the buildings were kept closed until 6 p.m. ET.
Montreal police spokesman Benoit Boisselle says no suspicious objects were found on the premises.
In a letter sent to several media outlets and consulted by The Canadian Press, a group threatened to detonate "small artisanal explosive devices" once a day until Friday in order to injure Muslim students.
The group, which described itself as a chapter of the Council of Conservative Citizens of Canada, or C4, complained about Muslim prayer services on campus and demanded the school stop "religious activities of all kinds."
Premier Philippe Couillard described the letter's content as "reprehensible" and said his government was monitoring the situation.
"My first concern is the safety of the young people, the students," he told reporters northeast of Quebec City.
"There doesn't seem to be a worry at the moment but we are following this very, very closely."
Police said the threats appeared in emails targeting one specific group, while Concordia president Alan Shepard held a news conference to say he has been in touch with Muslim student leaders.
"With the Muslim student association, we have a good relationship," he said. "They have good leadership and we're in close contact with them."
Shepard said he had no knowledge of reports that a letter warning of bomb threats was circulating Tuesday night.
He denied it took too long to empty the buildings.
"These are large complex buildings and we want to evacuate everyone safely," he said. "And we did it as soon as we safely could."