Lt. Pamela Castro of the Colorado Springs Police Department said police received a report of a shooting at Club Q at 11:57 p.m.
Castro said there was one suspect who was injured and was being treated. She said it was not immediately clear whether the attacker had been shot by officers. She said the FBI was on the scene and assisting in the case.
The police department tweeted that it planned an 8 a.m. news conference at its operations center.
Club Q is a gay and lesbian nightclub that features a “Drag Diva Drag Show” on Saturdays, according to its website.
“Club Q is devastated by the senseless attack on our community,” the club posted on its Facebook page. It said its prayers were with victims and families, and “We thank the quick reactions of heroic customers that subdued the gunman and ended this hate attack.”
Colorado Springs is a city of about 480,000 located about 70 miles (112 kilometers) south of Denver that is home to the U.S. Air Force Academy. The city has long been an epicenter of American evangelicalism. Focus on the Family, a prominent evangelical Christian ministry, is based in Colorado Springs.
In November 2015, three people were killed and eight wounded at a Planned Parenthood clinic in the city when authorities say a man opened fire because he wanted to wage “war” on the clinic because it performed abortions.
The motive behind Saturday's shooting was not immediately known but it brought back memories of the 2016 massacre at the Pulse nightclub in Orlando, Florida, that killed 49 people. And it occurred in a state that has experienced several notorious mass killings, including at Columbine High School, a movie theater in a Denver suburb in 2012 and a Boulder supermarket last year.
There have been 523 mass killings since 2006 resulting in 2,727 deaths as of Nov. 19, according to The Associated Press/USA Today database on mass killings in the U.S.