Toronto police responded to several bomb threats to post-secondary institutions around the city on Tuesday.

Police said they were first alerted to the situation at around 8:54 a.m.

“We’re investigating and working with schools to evacuate where necessary,” police said in a tweet.

Ryerson University said the Chang School was closed for a police investigation but has since reopened.

OCAD University evacuated all of its buildings but has been given the all-clear by police. The buildings will reopen on Wednesday morning for the regular summer schedule.

George Brown and Humber College also received threats, police said. They have since deemed both schools safe.

Humber college tweeted that “classes, services & operations are continuing as scheduled.”

Police say individual probes of each school have been completed but the investigation into the matter continues.