Chief executive of Twitter Jack Dorsey was the latest target of hacker group OurMine, which had earlier compromised social media accounts of Facebook head Mark Zuckerberg and Google CEO Sundar Pichai. The hackers on Saturday posted a view videos, followed by a tweet that read, “Hey, it’s OurMine. We are testing your security.”

The tweets appeared to have been shared from the Twitter chief’s linked Vine account, Engadget reported. The posts were taken down later. This is the first time that the hackers broke into a company chief’s own platform – Dorsey had posted the first public tweet after the microblogging website went live in 2006.

OurMine claims it tries to expose security flaws in users’ accounts by hacking into them. “We are just trying to let them know that nobody is safe,” the group had told online news portal Mic.