The change highlights co-founder Jack Dorsey-led Twitter's recent push into video, an area where it lags Facebook and Google's YouTube, and efforts to revive stalled user growth.
In another move, Twitter will start allowing video publishers to make money out of their content on Vine, its video streaming service.
Vine will use Twitter's Amplify Open program, which runs ads before a video starts playing.
Twitter previously restricted videos to 30 seconds. The new 140-second video limit also applies to Vine, which previously had a six-second limit.
Twitter also launched "Twitter Engage", a mobile app that allows users with a large number of followers to track their posts and see what their fans are tweeting about.
"It is a good effort and sits within their overarching video strategy in empowering content creators," said James Cakmak, an analyst at Monness, Crespi, Hardt & Co Inc.
"But it is not a silver bullet in alleviating the broader challenges in the business."
The company faces increasing competition in mobile video from Facebook Inc's Instagram and popular messaging app Snapchat.
Video tweets on Twitter have increased by more than 50 percent since the beginning of 2016, the company said in a blog post on Tuesday.
The microblogging site said some publishers would also be able to create videos that were as long as 10 minutes using its "professional publisher tools".
Instagram allows users to post videos as long as 60 seconds, while Facebook Live limits videos to 45 minutes. Snapchat has a limit of up to 10 seconds.
"Video is becoming increasingly central to the real-time conversations happening on Twitter," Jeremy Rishel, Twitter Inc's vice president of engineering, wrote in a blog post.
The news comes a day after Twitter said it bought London-based Magic Pony Technology, a machine-learning startup that specializes in working with images, to deliver better video and picture content.
Twitter's shares were marginally down in early trading on Tuesday.
© Thomson Reuters 2016
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