An esports tournament in the United States has ended in tragedy after a losing competitor opened fire on the event, leaving three people, including the shooter, dead and another 12 injured.

According to the LA Times, the shooter “targeted a few people” and shot at least five victims before taking his own life.

It is also reported that the shooter was a competitor who had been knocked out of the tournament.

Jacksonville sheriff Mike Williams confirmed the identity of the suspect as 24-year-old Baltimore man David Katz.

According to Tech Crunch, the two deceased are Elijah Clayton and Taylor Robertson.

The Madden 19 tournament, which was held at the GLFH Game Bar in Jacksonville, Florida, was being livestreamed on Twitch at the time of the shooting.

In the video, gunshots can be heard as the screen switches from gameplay to display a “controller disconnected” message, before the stream is eventually cut-off.

19-year-old professional gamer Drini Gjoka was competing in the tournament at the time of the attack.

He tweeted, “The tourney just got shot up. Im leaving and never coming back… I am literally so lucky. The bullet hit my thumb.”

EA, the publisher of Madden 19, also tweeted “We are aware of an incident at a sanctioned Madden Championship Series competition in Jacksonville. We are working with authorities to gather facts at this stage… This is a horrible situation, and our deepest sympathies go out to all involved.”

The two-day tournament, which had started on Saturday morning, attracted 256 players, each vying for a spot in the next round of the event and a $US250 cash prize.