Twitter Inc's chief security officer Michael Coates said in a Twitter post on Wednesday that he will be leaving the microblogging site.
Coates joined Twitter in January 2015 but will now be quitting to begin his own security startup. The move was announced internally a few weeks back, according to his Twitter post.
Twitter was not immediately available for comment on the departure.
Separately, the director of information security engineering at Alphabet Inc's Google, Michal Zalewski, said on Twitter that he would be leaving after almost 11 years.
Zalewski will join Snap Inc, a person familiar with the matter told Reuters.
Matthew Moore, who was earlier an engineering director at Google, also joined Snap as chief information security officer this year, according to his LinkedIn profile.
Gerhard Eschelbeck continues to lead the security team at Google.
On Monday, Facebook Inc's chief information security officer Alex Stamos was reported to be departing in August over disagreements in how the site should deal with its role in spreading disinformation.
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