A shooting Friday in Midland, Texas, left one person dead and nine others in the hospital, Mayor Lori Blong said.
A suspect remained in a standoff with officers about two hours after the shooting, police said.
The shooting started around 8 a.m. in one part of the city before ending up near a veterinary hospital.
It sounded like at least 40 shots were fired, said Andrea Mendias who works at an automobile body shop near the veterinary hospital.
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Video from Mendias showed a number of officers pouring out of the back of an armoured police vehicle. Police were also sending robots into the area.
Blong said the situation was still evolving.
“Officers are containing the situation,” she said.
Midland Memorial Hospital reported four were in the operating room and five others were in stable condition.
Midland, a West Texas city with about 140,000 residents, sits in the heart of the state’s oil region and was near the site of a deadly shooting rampage just six years ago.
In that shooting, a gunman who had been fired from his oil services job killed seven people and wounded two dozen others while firing at random while driving around the Odessa and Midland areas. The two cities are more than 300 miles (482 kilometres) west of Dallas.