Twitter is building a new feature that will allow users to post tweets as long as 10,000 characters, well beyond its current 140-character limit, technology news website Re/code reports.
An expansion of the limit to 10,000 characters would allow a tweet of more than 1,000 words with spaces between words and punctuation.
Twitter may launch the service toward the end of the first quarter but has not set an official date, Re/code said, citing sources familiar with the plans.
They said the character limit could change before the final version of the product is unveiled.
Jack Dorsey, the company's co-founder, who returned as chief executive in October, in a series of tweets did not say whether Twitter would expand the limit. But he did call it "a beautiful constraint."
He added that the company has seen more people sharing screenshots of text, which are a way to get around the 140-character limit.
"We're not going to be shy about building more utility and power into Twitter for people," Dorsey wrote in a screenshot of text that was longer than 140 characters.
"As long as it's consistent with what people want to do, we're going to explore it," he added.
The micro-blogging website, in an attempt to keep the current look for the Twitter timeline, is testing a version of the product that displays 140-character tweets but expands to reveal more content when users click on the tweet, Re/code said.
Twitter has been experimenting under Dorsey to make the service more engaging.
In the few months since Dorsey returned, Twitter introduced the 'Moments' feature, added polls to tweets, rolled out a "buy" button and replaced its star-shaped "favourite" icon with a heart-shaped icon called "like."
Twitter has come under increasing pressure to boost user growth and ad revenue.
It had its slowest user growth in 2015 - it now boasts just over 300 million users - and was eclipsed by photo-sharing app Instagram, owned by Facebook, which surpassed 400 million users last year.