Four World War I-era missile tips have been found at a building demolition site just southwest of downtown Detroit.

Detroit police Officer Jennifer Moreno says the city's bomb squad identified the munitions after they were discovered Thursday morning. A nearby office building was evacuated.

Moreno says the missile tips have been deemed safe and will be X-rayed "to determine if there is anything inside."

She adds that "if there is anything inside, it will be turned over to the" U.S. military.

Police are trying to determine why the missile tips were at the location and how long they had been there.