PENN HILLS (KDKA) — Three people were injured in a shooting incident at a swim club in Penn Hills Monday evening.

According to emergency officials, the shooting happened around 6:50 p.m. at the Olympic Swim & Health Club on Twin Oak Drive.

Officials say three men were wounded in the gunfire. One victim was shot in the chest, another suffered a shoulder wound and the third was hit in the leg.

“I heard pops, about eight or so, and then saw everyone running,” Stephen Kustra, a witness, said. “We had two lifeguards standing out here watching the swimmers in the water, and as soon as those gunshots went off, everyone from this side of the pool ran down to the other end.”

About 70-80 people were attending a private party at the club when the shots rang out, according to reports. They were at the outdoor pool area, which can be rented out.

Witnesses say two cars pulled up to the pool area and at least eight shots were fired.

DEVELOPING: Witnesses said two cars pulled up to pool area, at least 8 shots fired; 3 men wounded pic.twitter.com/0LeY8yAVdD — Ralph Iannotti (@IannottiRalph) May 31, 2016

“I heard about eight to 10 pops, and then I saw the people that were out in front of the building took off and ran and hid under cars in the parking lot, and the two cars that had backed in took off very fast out of the driveway,” said Mary Sullivan, another witness. “I didn’t even know what it was at first. We were just floored.”

Shell casings were found at the scene.

There’s no word on the victims’ conditions, but they are being treated at UPMC Presbyterian Hospital.

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Authorities are looking for suspects and no descriptions have been released.

People at the pool say the group that was throwing the party had rented out the pool before. The organizer of the group believes the incident may have been a vengeance shooting and the suspect or suspects were after one person in particular.

However, police have not released any information about what prompted the shooting.

Penn Hills Police are investigating.

Stay with KDKA for the latest on this developing story.