AT&T says it has fixed a nationwide outage that prevented its wireless customers from making 911 emergency calls. "Service has been restored for wireless customers affected by an issue connecting to 911. We apologize to those affected," the company officials said in a statement. The outage was serious enough to gain the attention of the Federal Communications Commission. The FCC chairman, Ajit Pai, said via Twitter that they are investigating what went wrong. NBC News reports: The company didn't say how widespread the outage was, but as reports poured in from across the country, Karima Holmes, director of unified communications for the Washington, D.C., government, said her office had been "advised there is a nationwide outage for AT&T." At 10:20 p.m. ET, about 10 minutes before AT&T gave the all-clear, DownDetector, a site that monitors internet traffic for real-time information on wireless and broadband carriers, indicated that outage reports for AT&T were clustered most prominently around New York City, Philadelphia, Washington, D.C., Chicago, Miami, Dallas, Houston, San Francisco, Los Angeles and Seattle. But emergency authorities across the country confirmed 911 outages and publicized direct police, fire and ambulance dispatch telephone numbers that AT&T customers should call in emergencies.