Police sources tell NY1 a Rikers Island correction officer was brutally assaulted by an inmate.

We're told the guard was punched about 20 times. 

The Department of Correction says the officer was simply giving the inmate an extra piece of bread before the incident.

The officer suffered injuries to his face, head and arm. 

Officials say he was treated at a medical clinic and then taken to the hospital for further examination.

The DOC says that inmate has been re-arrested and is being placed on punitive segregation.