WASHINGTON — As more credit card skimmers turn up around the D.C. area, authorities are warning consumers to be aware when buying gas or using ATMs.

The warnings come amid last week’s reports of skimmers at several 7-Eleven locations in Prince William County, Virginia.

There have been similar reports in Fairfax County, Virginia, where authorities reportedly removed 21 skimmers from 15 locations in the span of 12 months.

The scammers are upgrading their technology, too. Prince William County police warn of a new wave of skimmers using Bluetooth technology. Such skimmers are are located inside the pump and leave few visible warning signs.

AAA Mid-Atlantic recommends the following tips to keep your information safe:

• When buying gas, park at pumps close to the front door of the station if possible. Criminals usually install skimmers where clerks can’t see them.
• Use your cellphone to check for Bluetooth skimmers: Go into your phone’s Bluetooth settings and look at the available devices. If an available device is called a series of random numbers and/or letters, that may be a Bluetooth-enabled skimmer. (Needless to say, you probably shouldn’t connect with that suspect Bluetooth device.)
• Make sure the gas pump panel is closed and inspect the card reader at the pump. Look for signs of tampering. If it appears that the panel has been opened or that its security seal has been broken, tell the cashier. (For an example of what a broken security seal looks like, visit the Federal Trade Commission’s website.)
• Pay for your gas inside the store.
• Use cash instead of a credit card.
• Monitor your bank statements constantly. Look for overdraft notices. Stay vigilant even if things look OK: Crooks may have your information for a while before going on a spending spree. The FTC also has information on avoiding credit card fraud on its website.