WIESBADEN, Germany — Army and Air Force Exchange Service customers in Germany will not be able to purchase fuel at AAFES gas stations or use their fuel ration card at off-post Esso stations for a six-hour period Sunday morning, according to a news release.

The scheduled system outage will occur between 5 a.m. and 11 a.m., AAFES officials said Wednesday. During the shutdown, AAFES also will not be able to issue or replace fuel ration cards and customers won’t be able to do any transactions on their accounts.

The outage is necessary for AAFES to perform system maintenance and adjustments, according to the release.