At least five people were killed and 21 others injured, including three law enforcement officers, in multiple shootings between Odessa and Midland in West Texas on Saturday, according to authorities.

Medical Center Health System CEO Russell Tippin said as many as 13 victims were being treated at Medical Center Hospital in Odessa. One of those patients has died, he said.

Tippin did not say if the patient that died was among the five dead previously reported by law enforcement authorities.

Two patients have been released, two others are in serious condition and seven are in critical condition, meaning they are out of surgery, he said.

A patient under the age of two was transferred to another hospital for treatment, he said.

Tippin previously said that the hospital was treating 14 shooting victims. But he said that one of the patients he included earlier was injured in an incident unrelated to the shooting.

He said the hospital will remain on lockdown for the safety of patients and staff.

Odessa Police Chief Michael Gerke said the gunman was shot and killed at a Cinergy movie theater in Odessa and that no active shootings were ongoing. He said earlier reports of a second gunman had not been confirmed.

Gerke did not give a motive for the shootings, but said the attack began after a traffic stop just after 3 p.m. by a Texas Department of Public Safety trooper. The chief did not say what prompted the traffic stop.

The Texas Department of Public Safety released a statement that said before the vehicle came to a complete stop, the driver pointed a rifle toward the rear window of his car and fired several shots at the DPS vehicle, which had two DPS troopers inside. One of the troopers was hit by the gunfire.

The gunman fled, then started to shoot at people in multiple locations, including a Midland police officer and an Odessa police officer, they said.

At some point, the shooter ditched his gold Honda and stole a mail truck. He drove to the Cinergy theater where officers shot and killed him.

The DPS trooper is in serious but stable condition, according to DPS officials. The two other officers are in stable condition at a local hospital.

Gerke described the gunman only as a man in his mid-30s and did not give his name. The chief said authorities believe the man was the only gunman.

“We do believe we have the threat contained, but I can’t be 1,000 percent sure of that,” he said. "Once this individual was taken out of the picture, there have been no more victims."

The shootings began shortly after 4 p.m., with Odessa police reporting that one or possibly two people had been driving around Odessa shooting randomly at people. Midland police also reported a shooting inside a Home Depot in Odessa.

Midland police initially said they were looking for shooters in two vehicles, including one who was believed to be at the Cinergy movie theater and the other driving on Loop 250 in Midland. The vehicles were described as a gold or white small Toyota truck and a U.S. Postal Service van. Odessa police said a gunman had hijacked a mail truck.

The University of Texas of the Permian Basin, which was placed on lockdown, said on Twitter that law enforcement authorities were trying to "locate and contain a shooter." The university directed students to stay in their dorms or offices and not to open their doors.

A witness to the shooting, 28-year-old Dustin Fawcett, told the Associated Press he was sitting in his truck at a Starbucks in Odessa when he heard gunshots behind him.

He then heard more shots and spotted the shattered passenger window of a white sedan, he told the AP. That's when he thought, "Oh man, this is a shooting."

Fawcett told the AP that authorities responded quickly. When police pulled out their rifles and vests, he knew that "this is not a drive-by. This is something else, this is something bigger."

Several Texas political leaders offered condolences after the shootings.

Gov. Greg Abbott, who said he would visit Odessa on Sunday, said in a statement: "The First Lady and I are heartbroken over this senseless and cowardly attack, and we offer our unwavering support to the victims, their families and all the people of Midland and Odessa."

"The state of Texas and the Department of Public Safety are working closely with local law enforcement to provide resources as needed and deliver justice for this heinous attack."

Just this week, Abbott had held meetings with lawmakers about how to prevent mass more shootings in Texas in the wake of a deadly attack four weeks ago in El Paso, where a gunman killed 22 people at a Walmart.

President Donald Trump also tweeted that he had been briefed by his attorney general about the shootings.

"FBI and Law Enforcement is fully engaged. More to follow." he posted.

Democratic presidential candidate Beto O'Rourke, who had left the campaign trail four weeks ago to return to his hometown of El Paso after the mass shooting at a Walmart there, also sent his condolences to Midland-Odessa.

"Our hearts are with Midland, Odessa, and everyone in West Texas who has to endure this again," he said. "We need to end this epidemic."

This article contains material from the Associated Press.

Odessa police chief says at least 5 people were killed and 21 injured after a mass shooting in Odessa, Texas, in a "horrific" day.pic.twitter.com/kzDB7CeJS9

— MSNBC (@MSNBC)August 31, 2019

VIDEO: Odessa, Midland Police and Texas State Troopers confront Odessa/Midland shooting spree gunman behind Cinergy movie theaters in Odessa, Texas [KOSA-TV]pic.twitter.com/Ihqsc3e7X2

— Matthew Keys (@MatthewKeysLive)August 31, 2019