"I think it was clear that gays were targeted in Orlando and it does matter and it's tragic that they were targeted because of their sexual orientation," the Iowa Republican told CNN's Chris Cuomo on "New Day."
King has been a staunch opponent of LGBT rights activists, most visibly in recent years in the fight over same-sex marriage. In 2009, he condemned an Iowa Supreme Court decision that lifted a decade-long ban on same-sex marriage, saying it could put the Hawkeye State in danger of becoming a "gay marriage Mecca."
opened fire at Pulse, an Orlando gay nightclub, early Sunday morning, killing forty-nine people and wounding dozens more.
King said it was difficult to "draw the line" on whether a person previously investigated by the FBI should be automatically banned from legally buying a firearm.
"They interviewed (Mateen) two or three times and they decided to close the investigation ... so what do you do to draw the line?" he said. "I'm not willing to take the guns out of the hands of everyone who fits that category because we are denying them their right to defend themselves too."
King also said he broadly supported Republican presumptive presidential nominee Donald Trump's position on immigration, but reiterated his support of former presidential candidate Ted Cruz.
"I think he's (Trump) laid out some policies that we ought to embrace, but with his immigration policy I'd modify his immigration policy of not letting any Muslims into the United States by suggesting instead that we take Ted Cruz's position, which is let's suspend immigration from terrorist-sponsoring countries at least until we get a handle on this," he said.