HONOLULU -- AT&T Wireless officials said they are not sure of what caused service problems around Hawaii for customers.

The disruptions appeared to be sporadic, affecting customers in different ways depending on what type of device people have or what area they are in, AT&T representative Courtney Pendleton said. She said technicians are focused on fixing the problem.

AT&T store workers told customers the outages began at about 1 a.m. or 2 a.m. on Tuesday.

Some customers report being able to call out, but not receive calls. Other customers are not able to reach the Internet or make calls. Other phone owners said they have no service.

The problem stems from a "hardware issue," Pendleton said earlier in the day.

She said crews are working to fix the disruption. AT&T did not have a time frame for how long the repairs would take.

The representative said it would be up to each customer to negotiate a rebate with AT&T.