HOUSTON — Five people were killed and more than 20 others were injured in a brazen daylight drive-by mass shooting in the West Texas cities of Midland and Odessa on Saturday, as a gunman drove on the highways and streets opening fire on residents, motorists and shoppers, the authorities said.
The attack terrified two sister cities 20 miles apart with a combined population of 263,000 at the start of Labor Day weekend. Police officers and state troopers tried to keep drivers off the highways. A local university urged students and faculty to stay in their dorm rooms and offices. A television station in Odessa, KOSA-TV, evacuated their studio while they were covering the breaking news live on the air.
Three law enforcement officers were shot, according to the police. Officials said the gunman, a man in his mid-30s, was dead, although they declined to identify him or describe how he died.
The chief of the Odessa Police Department, Michael Gerke, said the motive was not known, but that the attack had begun as a traffic stop. He added that there had been reports of a second gunman but that they were not confirmed, and attributed the sightings to the chaotic situation.
“We do believe we have the threat contained, but I can’t be 1,000 percent sure of that,” Chief Gerke told reporters on Saturday.
Federal officials were monitoring the attack, and agents from the F.B.I. and other agencies were deploying teams to the region.
The mayor of Midland, Jerry Morales, said the shootings began shortly after 4 p.m. on Interstate 20 and Highway 191, which connects Midland to Odessa. As the attack was unfolding, the police in Odessa said on Facebook that a gunman was driving around “shooting at random people.”
Junior Bejarano, 20, a worker at the Twin Peaks restaurant in Odessa, had just finished cleaning a table when he heard a gunshot outside at about 4:30 p.m. “It was chaos in a matter of seconds,” he said. “People were screaming, flipping chairs, dropping plates.”
A few minutes later, he and other workers walked outside and saw several cars with bullet holes at a nearby intersection, in the turning lane of E. 42nd Street near Parkway Boulevard. He heard a woman screaming and ran to her car with his co-workers.
Inside, he said he saw a baby girl in a car seat whose face, shirt and lap were covered in blood. One of his co-workers, who is also a paramedic, checked on the child until on-duty paramedics arrived and said that she appeared to have been shot in the shoulder.
“She was conscious, but she was just covered in blood,” Mr. Bejarano said. “It was horrible to see something like that.”
Inside another car in the turning lane, Mr. Bejarano said an older woman was hyperventilating after a bullet had apparently passed through her car’s passenger window and then through her driver’s side window, just missing her.
“She was just shaking,” he said. She was bleeding, but the injuries appeared to be from the glass breaking, not a bullet. “She really couldn’t talk,” he said.
The shooting rattled Mr. Bejarano and others, who said they never expected to see their town’s name on national news and trending on social media.
Another witness, Ernest Villanueva, 24, said he was driving westbound on Interstate 20 from Midland to Odessa when he approached a blue pickup truck and a silver sedan riddled with bullet holes. The vehicles were empty, Mr. Villanueva said, adding that he saw Midland police vehicles heading toward Odessa.
In the chaos, the police responded to a call of gunfire at the Music City Mall, where television news station CBS 7 has its studios. As reporters were live on the air reporting on the shootings that left five dead, they were ordered by the authorities to leave the studio.
They continued to report the news through their microphones, describing a scene of trash and footwear left behind by shoppers running from the mall. After the police swept the mall and determined the reports of gunfire were unfounded, the reporters returned to the set.
The attack came just four weeks after one of the deadliest mass shootings in Texas history, when a 21-year-old gunman opened fire at a Walmart in the border city of El Paso on Aug. 3 and killed 22 people. Midland is about 300 miles east of El Paso.
The El Paso shooting remains raw in Texas, and the attacks on Saturday reopened some of the anxiety and fears for many, including lawmakers and law enforcement officials. A handful of those wounded in the Walmart shooting remain hospitalized, and the newly formed Texas Safety Commission held its second meeting on Thursday to discuss how to combat domestic terrorism and extremist groups in the state. Gov. Greg Abbott, who formed the commission following the El Paso shooting, was making plans to be in Odessa on Sunday morning.
Faith Sanchez, 20, a sophomore at Odessa College, said in a phone interview that the El Paso shooting had been weighing heavily on her mind. On Saturday, she was eating at a Texas Roadhouse with her family when word of the shooting spread.
“While we were eating, everyone was just kind of panicking and wondering if we should go outside,” Ms. Sanchez said. “They informed us that there was a lockdown.”
The sister cities of Midland and Odessa make up part of the cultural heart of West Texas, oil-and-energy towns in the Permian Basin that often thrive or languish depending on the price of oil. It is a solidly red region of Texas that wears its presidential connections with pride — Midland is the hometown of both former President George W. Bush and his wife, Laura Bush.
“We never thought this would happen here,” Ms. Sanchez said. “So many people are just in shock. We’re scared.”
Mariel Padilla, David Montgomery and Nicholas Bogel-Burroughs contributed reporting.