(CNN)[Breaking news updates]
11:50 p.m. ET: The driver is in custody and is undergoing various tests, including one for alcohol, authorities said.
11:45 p.m. ET: Officials don't yet know whether it was an accident or intentional.
11:44 p.m. ET: At least one dead and seven in critical condition, fire officials said. There were a total of 37 patients.
[Full story]
A car mowed down more than 30 pedestrians when it went up on the sidewalk and into the entrance of the Paris Las Vegas hotel, authorities said.
At least one person was killed and 37 others injured, Clark County Fire Chief Greg Cassell said. Of the injured, seven are in critical condition.
Authorities don't yet know whether the incident was an accident or intentional. The woman driving the car was in custody and was undergoing tests for alcohol and controlled substances, authorities said.
Rows of ambulances and police cars gathered at the scene, their lights flickering. Witnesses described a chaotic scene as people fled.
"Everyone was running ... and as I was running, I saw a car up on the sidewalk coming toward us," a witness told CNN affiliate KLAS. "I saw a lady, she didn't seem like she wanted to stop the car, she had both hands on her wheel and she was looking straight forward."
People scrambled to stop the driver, she said.
"I saw men running after her, yelling, 'stop, stop!' As she was passing, we saw people running after her. Everyone was so frantic and just running around."
Antonio Nassar, who was at the Strip, described a disturbing scene.
"The car rolled right in front of me. By the time I looked over to the right, all you could see was [her] driving away and people were bouncing off the front of the car, you can hear it," Nassar told the affiliate.
"The windshield is smashed at this point. She rode the sidewalk, she came to a stop at the Paris intersection, people are punching into the window ... she accelerated again and just kept mowing people down."
Traffic snaked down the streets as cars were diverted near the Paris Las Vegas hotel, where the Strip was shut down.
Major accident on S. Las Vegas Blvd., please avoid the area. SLVB closed between Harmon and Flamingo while we investigate. #LVMPDnews
— LVMPD (@LVMPD) December 21, 2015
Las Vegas Strip: Car mows down over 30 people; 1 dead - CNN.com