Federal investigators are examining a crash in which two Amazon Prime Air delivery drones struck a construction crane in Tolleson, Arizona, a city west of Phoenix, on Wednesday.

Tolleson police said the morning crash occurred in a commercial area near 96th Avenue and Roosevelt Street, according to FOX 10 Phoenix.

The National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA) have both opened investigations into the collision.

"The NTSB is investigating the collision Wednesday of two Amazon Prime Air delivery UAS (drones) into a crane in Tolleson, Arizona," the agency said in a post on X Thursday. 

The FAA told FOX Business Friday that the drones involved were two MK30 drones that "collided with the boom of a crane." No injuries were reported.

Amazon paused drone deliveries in Arizona on Thursday but said operations would resume Friday, FOX 10 reported. Amazon spokesperson Terrence Clark told the station that the company is cooperating with authorities and had already completed an internal review.

"We’re aware of an incident involving two Prime Air drones in Tolleson, Arizona. We’re currently working with the relevant authorities to investigate," Clark said on Wednesday. 

"Safety is our top priority, and we've completed our own internal review of this incident and are confident that there wasn't an issue with the drones or the technology that supports them," Clark added on Thursday. "Nonetheless, we've introduced additional processes like enhanced visual landscape inspections to better monitor for moving obstructions such as cranes."

The official cause of the crash remains unknown. The incident comes as the U.S. Transportation Department (DOT) considers new rules that would allow drones to fly beyond the visual line of sight of operators, a step officials say is critical to expanding commercial uses such as package deliveries.

The NTSB, DOT, Amazon and Tolleson police did not immediately respond to a request for comment from FOX Business.