Hundreds of students were gathered at The Party Venue in Greenville, near Dallas, to celebrate the start of a new term at Texas A&M Commerce College.
With 750 people in the building, someone with a semi-automatic rifle opened fire.
Graphic footage of the aftermath posted on social media showed several injured people on the ground inside the venue and dozens running away from the building.
“We’ve got a bunch of walking wounded,” a Hunt County deputy said on the scanner, according to a WFAA reporter.
The shooter was still at large several hours later.
Deputies were already at the scene due to a parking complaint when they heard gunshots coming from the back of the building, chief deputy of Hunt County Sheriff’s Department, Buddy Oxford, told reporters.
Three air ambulances took some victims to a trauma hospital, while others were taken to hospitals in Greenville, and neighbouring Quinlan and Commerce, officials told reporters at CBS‘ Dallas branch.
No official information has been offered about the identity or whereabouts of the shooter. The FBI were also at the scene on Sunday morning, Mr Oxford said.
Greenville, where students were attending the unofficial homecoming party, is 15 miles away from the university campus.
“Our thoughts and prayers are with the victims, families, and friends of those affected by this morning’s shooting in Greenville,” the university said in a statement.
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