Twitter is losing four members of its executive leadership team, including its product and engineering chiefs, CEO Jack Dorsey tweeted late Sunday night, as he struggles to revive the company's growth. The quartet of executives, including product head Kevin Weil and head of engineering Alex Roetter, chose to leave the company and take some time off, Chief Executive Officer Jack Dorsey said in a Twitter post. Separately, Twitter will this week add two new board members to help guide it through a turnaround, according to a person familiar with the matter who asked not to be identified because the information was private.

Twitter has failed to improve its site quickly enough to reverse a slowdown in user growth.

Twitter's head of media, Katie Jacobs Stanton, and human resources vice president Brian "Skip" Schipper are also leaving the San Francisco-based company, Dorsey said.