At least two people are dead and several others were injured when a school bus carrying pre-K students was involved in a collision and rolled over in rural Texas on Friday, authorities said.

Texas Department of Public Safety Sgt. Deon Cockrell said two people involved in the collision in Bastrop County, along State Highway 21 about 50 miles east of Austin, have died.

The Austin-Travis County Emergency Medical Services Department, or ATCEMS, said four of the injured were taken to hospitals by helicopter and three others were apparently taken to medical facilities by ground ambulance.

It later said all patients who needed medical attention had been taken to medical facilities.

The crash involved two other vehicles, including a cement truck, Cockrell said. It wasn’t immediately clear whether the people killed were in the bus or the other vehicles.

The Hays Consolidated Independent School District said in a statement that the bus was carrying Tom Green Elementary pre-K students returning from a field trip to the Capital of Texas Zoo in Cedar Creek, about 22 miles southeast of Austin.

It said 44 students and 11 adults were on the bus. The school is about 17 miles south of Austin. The district said its bus “was involved in a serious accident early this afternoon” and that “parents of students on the bus have been notified directly from the campus.”

Counselors and other district staff members were sent to the accident scene or to a reunification point set up for parents, the district said.

U.S. Sen. John Cornyn, R-Texas, said he’s praying for those who lost loved ones in the crash. “I am shocked and deeply saddened to hear about the school bus accident in Bastrop County today,” he said on social media platform X.

Authorities asked the public to avoid the area of the accident.