A "military artifact" was uncovered as archeological crews dug at a downtown construction site, Toronto police say.

Police said the artifact was uncovered at a dig site at Chestnut and Armoury Streets, near University Avenue and Dundas Street West, on Wednesday morning.

Crews have not confirmed exactly what the artifact is, but said it is believed to be some type of shell dating back to the First or Second World War. The area was home to a wartime armoury.

The city's chemical, biological, radiological and nuclear defence (CBRND) team was called in as a precaution. Pedestrian and vehicle traffic was also diverted around the area as officials investigated, but the roads have since been reopened.

Archeological discoveries like the military artifact are not uncommon during Toronto construction projects. This summer, an archeological team uncovered the remnants of an 1800s market under the St. Lawrence Market development. 

The wooden structure of an 1830s schooner was uncovered at a condo development site in May, and part of a 19th-century railway was found in the downtown area in April, 2011.