AT&T on Tuesday launched AT&T Call Protect, a free network-based service that gives eligible AT&T wireless customers with HD Voice the ability to block unwanted calls on their smartphones.

Tom Wheeler, the chairman of the Federal Communications Commission (FCC), called robocalls the number one complaint received by the agency. Robocalls are automated telephone calls that are often used by scammers and telemarketers. Wheeler urged major carriers, including AT&T, Verizon, T-Mobile, Sprint, U.S. Cellular, CenturyLink and Frontier, to take immediate action in making technology to block robocalls available for free to consumers.

“Nuisance calls are an industry-wide problem that unfortunately affect many people,” said Jeff Bradley, senior vice president, Device and Network Services Marketing, AT&T. “We’ve listened to our customers and know they want a network that provides tools to proactively assist in blocking nuisance calls. AT&T Call Protect, along with others, will help put customers more in control of the calls they receive.”

AT&T customers can access the network-based service and get more optional features, including temporary call blocking, by downloading the complementary AT&T Call Protect mobile companion app.