This year’s Comic-Con allowed attending fans the chance to see unreleased footage of forthcoming blockbusters but, thanks to some unwanted uploads, two major films have also seen their early trailers leaked online.

The previews for the eagerly anticipated antihero movies Suicide Squad and Deadpool were initially premiered in front of a live audience but covertly filmed and pirate copies surfaced online soon after.

Sue Kroll, the president of worldwide marketing and international distribution for Warner Bros, spoke out about the leak of the studio’s Suicide Squad trailer: “It’s unfortunate and ultimately damaging that one individual broke a long-standing trust we have enjoyed with our fans at the convention by posting early material, which, at this point, was not intended for a wider audience.”

Kroll said the film is still in production and added: “Our presentation yesterday was designed to be experienced in that room, on those big screens!”

The leaked footage, which offers a first look at the film starring Will Smith and Jared Leto, has already received more than 5.7m views. Warner Bros also unveiled a full-length trailer for Batman v Superman: Dawn of Justice at the event, which they released online soon after.

Suicide Squad will become part of DC’s new extended universe, with its tale of criminals working together set to connect with Zack Snyder’s Batman and Superman match up.

Marvel’s Deadpool trailer was a hit with fans after it premiered, with many claiming the character, played by Ryan Reynolds, stole the convention.