DETROIT _ A pedestrian bridge that once was part of a Packard auto assembly plant has collapsed, leaving a pile of rubble on a Detroit boulevard.

The city says no injuries were reported.

Joe Kopietz, a spokesman for site co-owner Arte Express, tells The Detroit News contractors at the site noticed bricks falling from the bridge Wednesday, and it collapsed about 3 p.m. He says the cause of the collapse is believed to be a pre-existing structural issue and temperature fluctuations.

The city also co-owns the bridge. The office of Mayor Mike Duggan says it's making plans to have a contractor remove the debris as soon as possible.

The bridge was erected in 1939. It had been off-limits to tour groups in recent years because of concerns about its structural integrity.