GLENDALE (CBSLA.com) — Officials Friday warned the public to be wary of an increased number of utility phone scams in Glendale.

A statement issued by the city of Glendale says many Glendale Water & Power clients have been contacted by people claiming to be customer service representatives.

READ MORE: Food Truck Crashes In Vernon; One Dead

The statement says the callers utilize sophisticated spoofing software that shows either “GWP” or an “818” number on the phone display.

READ MORE: `Solidarity' Cited In New Deal For 40k Behind-the-Scenes Film & TV Workers

The callers then reportedly ask the customer to pay their bill over the phone, directing them to buy a “Green Pack Money Card” or face immediate water or power shut-off.

“Customers … are given another local phone number and a specific time to call back and provide the money card information,” according to the statement.

MORE NEWS: Child, 18 Months, Killed in North Hills Crash

Those who have been called were asked to report the calls to the Glendale Police Department at (818) 548-4911. Customers were also urged to verify their account balance by calling GWP at (818) 548 3300.