City of Montreal engineers were inspecting a ten-storey University St. building Thursday after a 600-kilogram block appeared to have become unstable.

The three blocks of concrete on the façade of the building at 1240 University St. are of concern. They are located on the seventh, eighth and tenth floor of the building, which houses a Tim Horton's on the ground floor and nine floors of office space above.

The one-metre-by-one-metre block is was on the tenth floor, and was jutting out about three centimetres from the building and weighs nearly 600 kilograms.

University St. is closed between Ste. Catherine St. and Rene Levesque Blvd, and firefighters say the stretch could be closed for a few days.

No evacuations took place, and all businesses remained open on the first floor, as the structure of the building is not in danger of collapse.

Richard Lapointe from the Montreal fire department said the block could have come loose for any number of reasons, including the cold weather and vibrations from nearby construction.