Salim Modak, right, and his son, Affan, pray at the All Dulles Area Muslim Society (ADAMS) Center in Sterling, Va., Friday, Dec. 18, 2015.  Religious congregations across the United States are concentrating on safety like never before following a season of violence, from the slaughter unleashed in June 2015 by a white shooter at a historically black church in Charleston, S.C., to the killings this month in San Bernardino, Calif.  (AP Photo/Sait Serkan Gurbuz)

Security is the focus at churches, mosques amid heightened fears

Religious congregations across the United States are concentrating on safety like never before following a season of violence.