A hacker has taken over hundreds of Twitter accounts belonging to supporters of Islamic State since Sunday's attack at a gay nightclub in Orlando, using them to tweet gay pride messages and gay pornography, according to media reports including the Newsweek website.

The gunman in Orlando, Omar Mateen, who killed 49 people in his rampage, swore allegiance to ISIS in a call to police in the course of the incident.

"A hacker affiliated with the hacktivist collective Anonymous, who uses the online moniker WauchulaGhost, first began hijacking pro-ISIS Twitter accounts several months ago," Newsweek noted. Following Sunday's attack in Orlando, "the hacker decided to replace ISIS imagery posted to the accounts with rainbow flags and pro-LGBT messages," Newsweek reported.

“I did it for the lives lost in Orlando,” the hacker, who said he is based in the United States, told Newsweek. "The vigilante hacker claims to have taken over 200 Twitter accounts belonging to ISIS supporters. However, many have since been taken down by Twitter," Newsweek said, noting that ISIS has used social media for recruitment purposes and to spread its propaganda.

Original pro-ISIS content on the hacked Twitter accounts was replaced with messages such as “I’m gay and proud” and “Out and proud.” A link to a gay porn site was included in some of the hacked accounts, Newsweek reported, although no explicit images have been posted in respect to Islam.

“One thing I do want to say is we aren’t using graphic porn and our purpose is not to offend Muslims,” hacker WachulaGhost said. “Our actions are directed at jihadist extremists. Many of our own [group of hackers] are Muslim and we respect all religions that do not take innocent lives.”