Twitter Inc is planning company-wide layoffs next week, technology news website Re/code reported on Friday, citing sources.
The news comes after Jack Dorsey was appointed permanent chief executive on Monday.
It is unclear how many of Twitter's staff will be laid off, but it is likely it will affect most departments, Re/code said, citing company insiders.
The company employs about 4,100 people in more than 35 offices around the world, according to its website.
Twitter shares fell 3.1 per cent to $29.90 in extended trading on Friday.
The company is working to rekindle growth after its latest quarterly results in July revealed the slowest rise in monthly average users since it went public in 2013 - a performance that Dorsey at the time called "unacceptable."
Twitter's layoffs come at the same time as it restructures its engineering organization to make it more efficient, Re/code reported.
It is likely that many of the people impacted by the layoffs will be engineers, the report said.
"We're not commenting on rumour and speculation," a Twitter spokeswoman told Reuters.
Up to Friday's close, Twitter's shares had fallen about 14 per cent this year.
