ATLANTA — Georgia Power has reported a data breach impacting at least 300,000 out of 400,000 customers.

Georgia Power officials say the breach was discovered following recent suspicious activity in the company’s online customer portal.

Georgia Power says it is working with law enforcement. There is no evidence of ongoing unauthorized access, officials said. Georgia Power is in the process of notifying affected customers.

The company released the following statement:

“We recently detected suspicious activity involving our online customer portal. An unauthorized third party accessed certain, limited information about the accounts of approximately 400K customers. Upon detection, we took immediate steps to stop the activity and have engaged law enforcement. We have conducted a thorough investigation, and we have not identified any evidence of ongoing unauthorized access. We understand the trust our customers place in us and remain committed to protecting their information. We are in the process of notifying affected customers, along with providing free credit monitoring.”