In a 25-minute video dubbed "Flames of the Supporters" and posted on the Russian-based instant messaging service Telegram, the Sons Caliphate Army displayed photos of Facebook co-founder and CEO Mark Zuckerberg and Twitter CEO Jack Dorsey with digitally added bullet holes. Sons Caliphate Army is a purported hacking division of the Islamic State.
They also mocked the executives' attempts to block terrorist groups from using their social networks, showed hackers supposedly posting propaganda and boasting that they have they have hacked more than 10,000 Facebook accounts and more than 5,000 Twitter profiles.
The video was first spotted and reported by Vocative which said that a direct threat against Dorsey and Zuckerberg is made at the end of the video.
"You announce daily that you suspend many of our accounts, and to you we say: Is that all you can do?" the hackers say in text across the video. "You are not in our league.... If you close one account we will take 10 in return and soon your names will be erased after we delete your sites, Allah willing, and [you] will know that we say is true."
Officials at both Facebook and Twitter declined to comment on the video. The companies, however, have made it clear that they are pushing back against terrorist groups' efforts to use their networks.
Zuckerberg, speaking at the Mobile World Congress in Barcelona this week, said he doesn't want terrorist groups using Facebook to attract and train new recruits and celebrate attacks.
For its part, Twitter noted in a Feb. 5 blog post that it has suspended more than 125,000 accounts since mid-2015 for threatening or promoting terrorist acts -- largely related to ISIS. The company also said it has bolstered efforts to review reports of terrorists using the site, decreasing Twitter's in-house response time to any incidents.
"We condemn the use of Twitter to promote terrorism and the Twitter Rules make it clear that this type of behavior, or any violent threat, is not permitted on our service," the company wrote in the post.
With Twitter and Facebook moving to stop ISIS from using their networks, it's not surprising the terrorist group is pushing back, according to Dan Olds, an analyst with The Gabriel Consulting Group.
"Both Zuckerberg and Dorsey lead powerful social networking companies that have played a part in ISIS's recruiting," said Olds. "When the companies move to shut down ISIS on their networks, it's not surprising that they'd respond with threats."
He dismissed the latest threats and said they would do nothing to change Facebook's and Twitter's efforts.
"However, it would be a whole different ballgame if there is an organized physical attack on either the companies or their personnel," said Olds. "A successful attack might, unfortunately, change things considerably. But I think that both companies have probably beefed up security in light of these threats, so pulling off a successful attack wouldn't be easy."
Jeff Kagan, an independent industry analyst, said he suspects both Facebook and Twitter have turned up their security in light of the new threats but he doesn't see much else changing.
"The problem is we don't know what is serious and what is not," he said. "I think if this is the way the game is going to be played going forward, we'll just have to prepare and get used to this new reality."
Analyst Zeus Kerravala agreed: "Both Facebook and Twitter are big recruiting tools for ISIS so Zuckerberg and Dorsey are impeding the growth of the organization."