federal office buildings and passport offices. for 20 years, sixth graders in western massachusetts have traveled to washington, d.c., to see those landmarks. >> the government is mean. >> it's not really fair they get to choose how and when stuff doesn't open and stuff. >> reporter: for those that sent in their taxes by mail, tax refunds may not arrive. >> the cheetahs and other animals here at the national zoo will be fed even if the zoo is forced to shut down next week. and even if u.s. troops do not receive their paychecks, president obama and congressional leaders will continue to be paid on time. jake tapper, abc news, washington. >> we'll have more insight into the high-stakes budget talks with george stephanopoulos's exclusive interview with the republican leader boehner later on good morning america. and in other news, fbi chief, robert mueller, says that his agency is on guard against libyan agents who may be operating here and told a congressional committee the fbi is interviewing libyans in the united states including libyan