Authorities have been left puzzled after two pedestrians were hit by blow darts while crossing San Francisco's famous Golden Gate Bridge on Friday, according to the Associated Press. Neither victim was seriously injured during the incidents.

An officer for California Highway Patrol was stopped by a pedestrian Friday afternoon who reported that he had been hit in the leg by a metal dart that had apparently been fired from a blow gun, CBS San Francisco reported. 

The dart was approximately five inches long and had become lodged several inches into the man's skin through his jeans, according to the San Francisco Gate.

As officers were responding to the incident, another pedestrian walked up and reported that she had also had a dart fired at her, which had hit her in her knee, according to The Los Angeles Times. Both pedestrians were evaluated and released on the scene by paramedics.

California Highway Patrol was unable to explain the attack, with spokesperson Andrew Barclay telling reporters that the attack seemed "random" and that there didn't seem to be any motive for either of the victims' attacks. Both had been walking north on the east side of the bridge when they were attacked.

The darts were collected as evidence and are now being tested to make sure that they were not treated with any chemicals prior to being fired, CBS San Francisco noted. Authorities are also checking surveillance footage to see if the attacker was caught on camera.

"I've never heard of something like this," Barclay said. "Neither of them had had any arguments... It is really just reckless, careless, there's no purpose to fire those darts...without the intention of harming somebody."