Image copyright Kimberly White Image caption Twitter chief executive Jack Dorsey said the four departing executives could have some "well-deserved time off"

Four key Twitter executives are to leave the company as the social network continues its attempt to turn around its fortunes.

Twitter's head of product Kevin Weil and head of media Katie Jacobs Stanton are to leave the company in the coming weeks, as is Alex Roetter, Twitter's head of engineering. Skip Schipper, who was responsible for human resources matters, is also departing.

The news was confirmed in a tweet by chief executive Jack Dorsey on Sunday, who said the foursome could now have some "well-deserved time off".

Mr Dorsey - who co-founded Twitter - said when he returned to the company last month that he would make sweeping changes.

The first was to lay-off 8% of the company's workforce and it now seems changes are being made among top executives.

Also leaving is Jason Toff, head of Vine, Twitter's mini-video service. He tweeted that he was to join Google to work on virtual reality.

Shares in Twitter fell about 7% in early trading in New York on Monday and are down almost 60% over the past 12 months.

'The world needs Twitter'

Writing on blog site Medium, Ms Stanton said her decision was about "time".

"While I've poured my heart and soul into Twitter," she wrote. "I decided to resign because it's time for me to pour more of my energy into my family."

She later added: "The world needs Twitter and while I will turn in my badge in a few weeks, I will keep rooting (and tweeting!) for Twitter's continued success."

Technology news site Recode reported that the company will soon bring a "well-known media personality" to its board of executives, speculating that American Express's Leslie Berland has been lined up for the role.

Twitter's challenge since hitting the stock market in November 2013 has been to satisfy investors that the 140-character network can sustain growth. To date, it's largely failed, while newcomers like Snapchat and Instagram have not only captured a younger demographic, but also become sophisticated and lucrative media platforms in their own right.

Wooing users

The site's attempts to drum up added interest included a high-profile advertisement during American baseball's World Series.

The ad promoted a new feature called Moments, recently rolled out in the UK, which aims to collate news events into a series of key tweets. The goal was to move away from Twitter's sometimes-overwhelming chronological format.

The advert was poorly received, but it is too early to see if Moments has been a success.

As head of product, Kevin Weil was responsible for the roll-out of Moments, although he was under the watchful eye of Mr Dorsey, who took on a more hands-on development role than his predecessor, Dick Costolo.

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