Twitter CEO Jack Dorsey’s plans to revive the social network’s fortunes have been dealt a blow with the departure of several senior executives.

Head of engineering Alex Roetter, head of HR Brian Schipper, head of media Katie Jacobs Stanton and head of product Kevin Weil are all leaving Twitter, Dorsey yesterday confirmed in a tweet.

Stanton was responsible for working with media companies to secure premium content for the Twitter platform.

Jason Toff, head of video service Vine, is also leaving Twitter to join Google to work on the development of its virtual reality products.

Dorsey wrote: “Was really hoping to talk to Twitter employees about this later this week, but want to set the record straight now.

“Given the inaccurate press rumours today regarding their departures, I’m addressing this now: I’m sad to announce that Alex Roetter, Skip Schipper, Katie Stanton, and Kevin Weil have chosen to leave the company […] All four will be taking some well-deserved time off.”

Dorsey said that chief operating officer Adam Bain will take on “additional responsibilities” in the meantime, while, according to a CNBC report, head of commerce Nathan Hubbard has been appointed interim head of media.

Earlier this month, it was revealed that Twitter is testing a new interactive ad format which encourages the public to retweet brand messages organically to their followers.

Twitter is also rumoured to be opening up to longer conversations with the introduction of 10,000 character tweets, following a tweet hint by Dorsey.

Last week it was announced that Twitter is to partner with Festival of Media Asia Pacific Awards for the launch of a new Live Marketing Award category.