(Reuters) - UnitedHealth Group ( UNH ) said on Thursday a service provided by its Change Healthcare unit was facing an issue receiving batches of medical claims from customers.

A fix has been implemented and is being monitored to ensure operability, Optum, a unit of UnitedHealth ( UNH ) which operates Change, said in a statement.

UnitedHealth ( UNH ) did not immediately respond to a Reuters request for comment on the severity of the issue. It was not clear if the latest incident was related to a widespread hack in February.

The company was still working on resuming operations that were disrupted by the February hack, and on Tuesday said it expects a hit of up to $1.6 billion this year from the cyber attack.