Cryptocurrency investment platform Atlas Quantum announced on Sunday a data breach that exposed the personal details of all of its users.

The breach affected roughly 261,000 customers, according to data breach index site Have I Been Pwned, which received a copy of the data.

The stolen data supposedly included customers names, phone numbers, email addresses, and account balances.

New breach: The Atlas Quantum cryptocurrency investment platform had 261k names, phone numbers, email addresses and account balances exposed. 24% were already in @haveibeenpwned. Read more: https://t.co/MKqKLF7WvP — Have I Been Pwned (@haveibeenpwned) August 27, 2018

Atlas Quantum confirmed the breach on Sunday night, in a Facebook note. The company said it's currently investigating the incident.

The platform lets users add Bitcoin to their accounts to buy and sell on various cryptocurrency trading platforms, allowing users to make profits based on Bitcoin's price fluctuations and the differences in exchange rates.

Atlas Quantum said the hacker (or hackers) did not steal any funds from users' accounts.

"At the time of the incident, we took immediate steps to protect the database and passwords and private keys remain encrypted," reads the translated message from Atlas Quantum.

The company said it disabled some platform features as it's investigating the incident but promised to notify users when they were reactivated.

"We are monitoring the affected accounts and working to have additional protection against fraud," an Atlas Quantum spokesperson said.

It is believed that Atlas Quantum's entire userbase was affected. Users can check if their details were stolen in the incident via the Have I Been Pwned portal.