ISIS might have a new target: Twitter employees.

After the site began cracking down on the terrorists, suspending their Twitter accounts, its staff received a slew of death threats from the Islamic fighters, the company’s CEO Dick Costolo told Vanity Fair.

Costolo did not detail the contents of the messages, but said ISIS fighters threatened to “assassinate” him and other Twitter employees.

“That’s a jarring thing for anyone to deal with,” he said.

The shut-down accounts were used to promote terrorism and discuss violence — topics forbidden under the site’s terms of service. The social media giant has long refused to give criminals a voice online, he said.

“It’s against the law in many of the countries in which we operate for them to use it to promote their organization,” Costolo said. “And when we do find those accounts we shut them down. We shut them down quite actively.

ISIS has proven itself to be an especially social media-savvy organization. While Twitter shuts down accounts when it finds them, plenty of terrorists have used the site to discuss their mission and connect with other fighters before being ousted.

Keep reading…