Insurance giant Aflac identified “suspicious activity” in its U.S. network, which initiated its cybersecurity protocols. Aflac said it was able to stop the attack within hours, and its systems were not affected by ransomware.

The insurer said it’s in the early stages of a review of the incident, and so far is unable to determine the total number of affected individuals.

Aflac has confirmed a cybersecurity breach that may have compromised sensitive customer information. The company is the latest target in a string of attacks on major insurance providers. The company said the intrusion was first detected on Thursday,