April 18 (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.