ANCHORAGE, Alaska (AP) — The U.S. Postal Service has prohibited employees from providing witness signatures for absentee ballots while they are on duty. That could make voting by mail more difficult for some Alaska residents. The Anchorage Daily News reports that the nationwide rule passed earlier this year could cause problems for rural residents. Absentee ballots in Alaska and several other states must be signed by witnesses who can verify ballot were legitimately filled out by voters. Alaska Division of Elections Director Gail Fenumiai says postal officials are sometimes the only authorized witnesses available in areas of rural Alaska.