A 22-year-old gunman opened fire, killing five people and wounding 25 at a gay nightclub in the western U.S. city of Colorado Springs, Colorado, with other patrons at the club subduing him before police arrived, authorities said Sunday.

Colorado Springs Police Chief Adrian Vasquez said two weapons, including a "long rifle," were found at the scene of the Saturday night shooting at Club Q, which describes itself as an 'adult-oriented gay and lesbian nightclub hosting theme nights such as karaoke, drag shows & DJs.'

Investigators said they were still trying to determine a motive for the shooting, but El Paso County District Attorney Michael Allen said authorities were looking into whether it should be prosecuted as a hate crime.

Police identified the gunman as Anderson Lee Aldrich, who was in custody and being treated for injuries. No charges were filed immediately pending further investigation.

Lieutenant Pamela Castro told a news conference shortly after the shooting that police got the initial phone call just before midnight.

On its Facebook page, a statement from Club Q said it was 'devastated by the senseless attack on our community ... We thank the quick reactions of heroic customers that subdued the gunman and ended this hate attack.'

'At least two heroic people' confronted the gunman and stopped the shooting, Vasquez said. 'We owe them a great debt of thanks.'

Of the 25 people injured, some were in critical condition and at least two had been treated and released, officials said, adding that some were hurt trying to flee.

U.S. President Joe Biden said that while the motive for the shootings was not yet clear, 'We know that the LGBTQI+ community has been subjected to horrific hate violence in recent years.

'Places that are supposed to be safe spaces of acceptance and celebration should never be turned into places of terror and violence. Yet it happens far too often,' he said. 'We must drive out the inequities that contribute to violence against LGBTQI+ people. We cannot and must not tolerate hate.'

A makeshift memorial sprang up Sunday near the club, with flowers, a stuffed animal and candles in front of cardboard sign with the message, 'Love over hate' next to a rainbow-colored heart.

The shooting was reminiscent of the 2016 massacre, at the Pulse gay nightclub in Orlando, Florida, that left 49 people dead. The Club Q incident occurred in a state where other mass killings have also taken place, including at Columbine High School in 1999, a movie theater in suburban Denver in 2012 and a Boulder supermarket last year.