A crowd vandalized a Waymo self-driving robot-taxi owned by Alphabet’s autonomous driving unit. The crowd set the vehicle on fire by throwing a firework inside the car in San Francisco on Saturday.

According to Waymo, the self-driving car was navigating through Chinatown at about 9 pm when a crowd suddenly surrounded it. Someone in a crowd broke the car window and threw a firework inside, setting the vehicle ablaze. Although, the company did not state what caused the crowd to attack the car.

Video footage on social media showed a large crowd tagging the vehicle before other crowd members began to smash the car’s windows and attempt to open it. Other videos showed the vehicle burning as a crowd formed around it.

Waymo officials confirmed in a statement that no injuries were reported, and they were working closely to respond to the situation.

“The vehicle was not transporting any riders and no injuries have been reported. We are working closely with local safety officials to respond to the situation,” a spokesperson for the company said.

A witness to the incident, Michael Vandi, told the reporters that people had been celebrating China’s Lunar New Year and setting off fireworks before the event occurred.

Vandi also confirmed that someone jumped onto the car’s hood and broke the windshield. He noted that nearly 30 seconds later, another person also jumped onto the hood, with someone from the crowd encouraging them.

This incident occurred just a few days after a Waymo self-driving car hit a bicyclist. Last October, a GM autonomous Cruise vehicle dragged a pedestrian on the road for 20 feet (six meters). The incident led California to suspend the operation of Cruise robot taxis in the state over safety concerns.

According to a local media report, the incident comes at a time when Waymo is facing increased scrutiny. Despite regulatory challenges, Waymo has been expanding its operations, with plans to launch a complete range of robot taxis in Los Angeles.