Hang up the phone or close the door on scammers, Hawaiian Electric Co. said in a warning to customers Wednesday.

HECO said common scams include individuals claiming to be employees of electric, natural gas, or water providers and demanding immediate payment, claiming the targeted customer’s service will be disconnected if the payment is not made. Scammers typically reach customers either in person, over the phone, or online, HECO said.

“These criminals can be very convincing and often target those who are most vulnerable, including small-business owners, seniors and non-native English speakers,” HECO said in a statement. “However, with the right information, customers can learn to avoid and report these predatory scams.”

One sign of a scam is the caller requiring a prepaid card, a wire transfer, or similar forms of payment. Other red flags include requests for bank account numbers, usernames and passwords, credit card numbers or Social Security numbers.

HECO said that if customers believe they have been targeted by a scammer, customers should delete all emails that demand immediate payment or personal information, contact local police or contact the Federal Trade Commission at ftccomplaintassistant.gov.

Customers of HECO, Maui Electric Co. and Hawaii Electric Light Co. on Hawaii island can call a nearby service center to report suspicious calls:

>> Oahu: 548-7311

>> Maui: 871-9777

>> Molokai and Lanai: 877-871-8461

>> Hilo: 969-6999

>> Kona: 329-3584

>> Waimea: 885-4605

For more tips and resources to help identify and avoid utility scams, visit eei.org.