Rapper Travis Scott is speaking out after eight people were killed during his concert Friday night.

"I am absolutely devastated by what took place last night," he tweeted Saturday. "My prayers go out to the families and all those impacted by what happened at Astroworld Festival. Houston PD has my total support as they continue to look into the tragic loss of life.

"I am committed to working together with the Houston community to heal and support the families in need. Thank you Houston PD, Fire Department and NRG Park for their immediate response and support."

At least eight people were killed and many others injured when a crowd surged toward the stage at the Astroworld Festival at NRG Park. About 50,000 people attended. The festival was created by the Houston-born rapper, who has a daughter with Kylie Jenner.

The crowd "for whatever reason began to push and surge towards the front of the stage, which caused the people in the front to be compressed," Houston Fire Chief Sam Peña told CNN Saturday morning.

More than 300 people were treated at a field hospital set up near the festival, Peña said.

Twenty-three people were taken to hospitals, and eight of them died, Peña said. One patient is 10 years old, and at last check was in critical condition, Peña told CNN Saturday morning.

Some of the patients were in cardiac arrest as they were taken to hospitals, Peña said. Further details about the injuries weren't immediately available. The causes of death will be determined by a medical examiner, he said.