Company warns users they should reset their passwords.
US web-link shortening service Bitly has warned its that the personal details of its users may be under threat.
Although the company said there is no evidence as yet to suggest of a hacking attempt, as a precautionary measure, the service has been disconnected from all users' Facebook and Twitter accounts.
In a company blog, Bitly's CEO Mark Josephson said: "We have reason to believe that Bitly account credentials have been compromised.
"We have no indication at this time that any accounts have been accessed without permission."
However, he assured customers that "The team has been working hard to ensure all accounts are secure," and outlined a series of steps for the users to protect their accounts.
Users are advised to change passwords, and reset the system's API key and OAuth token post, following which they can reconnect their social media accounts to the service at the next login.
Launched in 2008 in New York, Bitly is a popular service that enables users to create shortened or customized URLs. It also helps people to track sharing of the shortened link over time.
The service originally served as the default link shortener for Twitter, till the site developed its own service in 2009.