An unspecified problem put cell phone towers out of service Saturday evening, leaving some AT&T customers without wireless service.

Most of AT&T's wireless network was believed to be working again early Sunday morning. Late Saturday, AT&T tweeted about the issue and said crews were working to restore service.

"Los Angeles area AT&T customers may have issues with wireless service," the company said in a statement. "We are working now to resolve. We apologize for any inconvenience."