Dick Costolo quits as Twitter chief
The chief executive of Twitter has quit the social network.
Dick Costolo announced that he had decided to leave the California-based company at the beginning of July.
In a statement, he said: "I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company.
"We have great leaders who work well together and a clear strategy that informs our objectives and priorities."
He added: "I am deeply appreciative of the confidence the board, the management team and the employees have placed in me over the years, and I look forward to supporting Twitter however I can going forward."
Mr Costolo's departure comes just months after he admitted that Twitter "sucks" at dealing with abusive behaviour and content, which in the past has seen a host of high-profile users quit the social network over abuse they received.
He said at the time that he took personal responsibility.
Twitter's board of d irectors named Jack Dorsey, the site's co-founder and chairman, to serve as interim chief executive while a replacement is found.
Mr Costolo will continue to serve on Twitter's board of d irectors, the company said.
He said of his interim successor: " There is no-one better than Jack Dorsey to lead Twitter during this transition.
"He has a profound understanding of the product and Twitter's mission in the world as well as a great relationship with Twitter's leadership team."
Mr Dorsey said: "The future belongs to Twitter thanks in large part to Dick Costolo's dedication and vision. Dick has put a world-class team in place and created a great foundation from which Twitter can continue to change the world and grow."