Police say there are multiple gunshot victims after a suspect hijacked mail truck in Odessa, Texas.
Local officers said two gunmen are at large after a reported shooting at a home improvement store.
One person has reportedly been arrested.
Eyewitness video captured police responding to the shootings, with sirens blazing as vehicles raced up and down roads in the state.
In a post on its Facebook page, Midland Police Department said: "There are reports of an active shooter at the Home Depot in Odessa.
"For the safety of the public and law enforcement please stay away from the area and stay in your homes."
It later updated the post to reflect: "We believe there are two shooters in two separate vehicles.
"One suspect is believed to be at the Cinergy in Midland and the other is believed to be driving on Loop 250 in Midland.
"The two vehicles in question are: gold/white small Toyota truck and a USPS Postal Van."
The University of Texas Permian Basin campus has gone into lockdown. There have been no reports of fatalities.
The Texas Department of Public Safety has urged residents to avoid major highways in the area, including Interstate 20.