A reported mass shooting has unfolded at a Texas university event, with fears as many as 20 people have been injured.

Local media report that a gunman opened fire at a Homecoming party for Texas A&M Commerce in Greenville on Saturday night (local time).

Graphic vision uploaded to social media shows those in attendance frantically attempting to administer CPR to the injured.

It's understood hundreds of people had been at the party celebrating the start of the school year. More than 100,000 people had attended a Texas A&M college football game earlier in the day.

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Ground and air ambulances are at the scene, with a police scanner from the area suggesting one person had been shot in the neck.

Jason Whitely, a reporter for local ABC affiliate WFAA said that at least two people had been killed, however officials are yet to confirm any fatalities.