BOVINA, Miss. — Investigators with the National Transportation Safety Board were collecting evidence Sunday at the scene of a commercial bus crash in Mississippi that killed seven people and injured dozens of others.

The 2018 Volvo bus was traveling westbound on Interstate 20 near Bovina early Saturday when a left front tire failed and the vehicle veered onto an embankment and overturned onto its left side, NTSB member Todd Inman said at a news conference Sunday.

Six people aboard were pronounced dead at the scene and another died at a hospital, according to the Mississippi Highway Patrol. Thirty-six people were taken by ambulance to hospitals.

The highway patrol did not immediately have an update on their conditions Sunday.

The dead included a 6-year-old boy and his 16-year-old sister, according to Warren County Coroner Doug Huskey. They were identified by their mother. Authorities were working to identify the other victims, he said.

The bus was traveling from Atlanta to Dallas with 41 passengers and two drivers, the highway patrol said. No other vehicles were involved in the crash.

Inman said investigators will look at the vehicle’s condition, including how well the tires were maintained. The investigation will also focus on road conditions, the driver’s experience, the carrier’s safety record and what protections were provided for bus occupants, he said.

Inman asked any potential witnesses to call Mississippi authorities.

A preliminary report was expected within 30 days and the full investigation could take up to two years, the NTSB said.

The bus was operated by Autobuses Regiomontanos. A woman who answered the phone at its Laredo, Texas, office said it was aware of the crash, but she didn’t answer questions or provide her name.

The transit company says it has 20 years of experience providing cross-border trips between 100 destinations in Mexico and the U.S. Its website promotes “a modern fleet of buses that receive daily maintenance,” and offers “trips with a special price for workers.”