DENVER (AP) — Two men were killed and five other people were injured in a shooting after a confrontation at a private, after-hours motorcycle club in Denver over the weekend, police said.

Denver police Lt. Matt Clark says they are investigating the shooting that happened around 3 a.m. Sunday outside the Hell’s Lovers Motorcycle Club.

At least two guns were fired during the incident, police said Monday.

“And anytime we look at these with multiple victims, multiple guns being fired, we consider the possibility that people who may have been hit by gunfire also had a gun and discharged one,” Clark said at a news conference on Sunday.

Shareef Aleem, a Park Hill resident who lives nearby, told The Denver Post he was awakened just after 3 a.m. and heard about 20 gunshots, which he initially thought was fireworks.

“For about three to five seconds, it was like silence. Then, everybody was screaming,” he said.

He watched people jump into their cars and speed away in the aftermath, he said.

Two of those who were injured have been released from the hospital and the other three are expected to survive their injuries, Denver police said Monday. All of those involved were adults and a woman was among those who were injured, police said.

No arrests have been made by early Monday afternoon, but KMGH-TV crews saw SWAT officers lead five men out of the club and that three were handcuffed.

Police are seeking additional witnesses to help determined what happened and find any other potential suspects, Clark said.