AT&T, Verizon and T-Mobile challenge rule targeting robocalls

The nation’s largest wireless carriers are lobbying to delay a new regulation on robocalls aimed at overseas scammers who make them, citing concerns that the rule could end up blocking legitimate calls.

The Federal Communications Commission rule, set to take effect Sept. 28, would require foreign-based phone companies to step up efforts to fight illegal robocalls or risk being blocked from sending calls to the U.S.

Many of the billions of robocalls annoying Americans emanate from India, the Philippines and other countries. FCC officials say the regulation, known as the foreign provider prohibition, would allow them to better trace the sources of illegal calls and block companies that carry them.