June 20 (Reuters) - Aflac ( AFL ) on Friday disclosed a

cybersecurity incident in which personal information of its

customers may have been compromised, making it the latest

insurance provider to be targeted.

The health and life insurance firm said the attack on its

U.S. network, which was identified on June 12, was caused by a

"sophisticated cybercrime group", but did not specify a name.

It said it was unable to determine the total number of

affected individuals until a review, which is in its early

stages, is completed.

The company said it was able to stop the intrusion within

hours and has reached out to third-party cybersecurity experts

to investigate into the incident.

The company said the potentially impacted files contain

personal information of its customers, such as social security

numbers and health-related details.

Aflac ( AFL ) offers accident and pet insurance plans in the U.S.

and Japan. It manages personal, medical and financial data of

more than 50 million policyholders.

Health insurers have been facing increased cybersecurity

risks recently with UnitedHealth's ( UNH ) breach being the most

notable example impacting 100 million people last year.

UnitedHealth's ( UNH ) Change unit was breached by a hacking

group called ALPHV, also known as "BlackCat" who are estimated

to have stolen a third of Americans' data in one of the worst

hacks to hit the U.S. healthcare sector.

Shares of Aflac ( AFL ) fell 1.3% in premarket trading.