Some normally busy downtown roads near the Rideau Centre remain closed after a section of the former Ogilvy's Department Store partially collapsed while undergoing demolition.

Firefighters said just after 5:30 p.m. Saturday a section of a wall collapsed and some bricks pushed a safety wall into a pedestrian walkway.

All of the construction workers escaped safely and there were no injuries reported.

But police closed Nicholas Street between Rideau and Daly streets, as well as Besserer Street west of Dalhousie Street leading to the Rideau Centre.

Rideau was also down to one eastbound lane. Commuters are asked to take other routes as a result.

Demolition sped up for Rideau Centre expansion

The City of Ottawa had sped up the demolition of the 105-year-old building as part of the Rideau Centre's expansion plan.

The building had been boarded up for 20 years and the owner of the Rideau Centre, Cadillac Fairview Corp., is demolishing it to include it as part of the $250 million mall expansion plan.

But that plan was only able to move ahead if the first three floors were preserved.

The fourth and fifth floors, which were constructed in the 1930s, are not going to be preserved.

A City of Ottawa staff report had indicated the building was deteriorating and must be removed "immediately" if the expansion will be finished by the summer of 2015.