The American Battle Monuments Commission said all the cemeteries and monuments it manages are closed for the duration. It also said it cannot respond to queries about its operations.
"ABMC will resume normal operations when a new funding measure is passed by the U.S. Congress and signed by the President of the United States," the agency said on its website.
Almost 125,000 U.S. service members are buried at 24 military cemeteries overseas, including thousands who died in the World War II invasion of Europe that began on D-Day in 1944. Another 94,000 people listed as missing in action are honored by monuments.
There are eight cemeteries dating from World War I in Britain, Belgium and France, 14 World War II cemeteries in France, Belgium, the Netherlands, Italy, Luxembourg, Britain, Tunisia and the Philipppines, a cemetery in Panama where people who died during the construction of the Panama Canal are interred, and the oldest overseas military cemetery in Mexico City for those killed in the Mexican War.