Addressing the media after the incident, Odessa Police Chief Michael Gerke ruled out the possibility of there having been a second gunman, as authorities had initially warned, Efe news reported. Meanwhile, the police department in Midland announced on its website that the suspected shooter was shot and killed at the Cinergy community entertainment centre in the town of Odessa.
"It has been confirmed that the active shooter was shot and killed at the Cinergy in Odessa. There is no active shooter at this time. All agencies are investigating reports of possible suspects," said the police, who had previously talked about two suspected gunmen driving separate vehicles.
Gerke said that the suspect's motives remained unknown, although the incident began after two Texas Department of Public Safety officers pulled over his vehicle on a Midland highway.
The suspect then opened fire on the officers and, after driving away, began shooting at other people in several locations. He later abandoned his vehicle and stole a US Postal Service van, the BBC reported. Initially it was suspected that two people were involved in the shooting and police had said they were believed to be driving around separately in a gold/white-coloured Toyota vehicle and a stolen US Postal Service van.
Odessa's Medical Centre Hospital said a child under the age of two was among those being treated there, while seven other of its patients were in serious condition. In a Facebook post, the Midland Police Department said: "There is no active shooter at this time. All agencies are investigating reports of possible suspects."
Three police officers were also among the injured. Texas Attorney General Ken Paxton said in a statement that he was "horrified to see such a senseless act". During the shooting, authorities urged public to get off the road "and use extreme caution".
US President Donald Trump said he has been briefed about the incident by Attorney General William Barr. "FBI and Law Enforcement is fully engaged," he tweeted. Firearms caused nearly 40,000 deaths in the US in 2017, which was highest in 50 years, according to official data.
In another statement, the state's Governor Greg Abbott said: "We will not allow the Lone Star State to be overrun by hatred and violence. We will unite, as Texans always do, to respond to this tragedy."
US Vice President Mike Pence said he and the Trump administration "remain absolutely determined to work with leaders in both parties in Congress to take steps that we can address and confront this scourge of mass atrocity in our country".
Just four weeks ago, Texas witnessed one of the deadliest mass shootings in the country's history on August 3, when 22 people were murdered in El Paso town, near the Mexico border. Hours after that attack there was another shooting in Dayton, Ohio, in which nine people were killed, as well as the shooter.
(With agency inputs)