The US National Highway Traffic Safety Administration opened a preliminary evaluation following incidents of automobiles “encroaching on pedestrians present in or entering roadways,” according to documents released Tuesday. The probe covers 594 Cruise vehicles.

The agency said it has received two reports involving pedestrian injuries that were sustained from Cruise vehicles under a June 2021 order demanding carmakers and technology companies report the incidents. NHTSA also said it identified two additional relevant incidents using videos that were posted to social media websites.

No fatalities have been reported in connection with the vehicles included in the investigation.

Cruise has been in regular communication with NHTSA and plans to continue cooperating with the agency, company spokeswoman Hannah Lindow said via email following the launch of the investigation.

“Cruise’s safety record over 5 million miles continues to outperform comparable human drivers at a time when pedestrian injuries and deaths are at an all-time high,” Cruise said.

One of the incidents involved a hit-and-run accident in San Francisco on Oct. 2 in which a human driving a non-Cruise vehicle struck a pedestrian, throwing the person in front of a Cruise robotaxi. The self-driving car stopped but still made contact with the person, NHTSA’s report said. The other vehicle fled the scene, and Cruise said at the time that it was “actively working with police to help identify the responsible driver.”

Another incident in San Francisco occurred in August when a Cruise vehicle was stopped at an intersection and started moving when the light turned green. A pedestrian then stepped into the crosswalk. Cruise’s AV tried to swerve and stop but struck the pedestrian at 1.4 miles per hour. The person went to the hospital complaining of knee pain.

Cruise operates robotaxis in San Francisco and has been expanding to other cities including Austin and Phoenix.

The NHTSA probe was reported earlier by Reuters.