"We were down ... and now slowly coming back up. Sorry!," Chief Executive Officer Jack Dorsey said in a tweet https://twitter.com/jack/status/1149412372651499520.
The interruption was due to an internal system change, the company said, adding that it was working to fully fix the problem.
Outage tracking website Downdetector.com earlier showed that there were nearly 70,000 people across the globe reporting issues with Twitter.
Shares of the company were marginally down in extended trading.
(Reporting by Munsif Vengattil in Bengaluru; Editing by Anil D'Silva)