Hurricane Olaf (search) passed within 60 miles of the U.S. territory's main island of Tutuila early Wednesday and then blew directly over a nearby group of smaller islands.
Telephone service to the Manua Islands of Ta`u, Ofu and Olosega was interrupted and officials were waiting for reports of damage after the storm crossed the area at about noon EST.
The Manua Islands are home to about 2,000 people.
Olaf had wind gusts up to 190 mph, and giant waves were likely to cause flooding in low-lying areas, the weather service said.
Gov. Togiola Tulafono had already declared a state of emergency Tuesday and asked President Bush to issue a disaster declaration as officials warned of an "extremely dangerous" storm.
However, Tutuila was not hit as hard as initially expected, and Tulafono ordered government workers to return to their jobs Wednesday. He said the territorial government would operate normally on the main island.
Schools remained closed, but teachers were told to report to prepare for resumption of classes on Thursday.
Two landslides were reported on Tutuila's north shore.
The three hardware stores in Pago Pago ran out of plywood and generators as residents prepared for the approaching storm, and the Samoa News, the territory's only daily newspaper, canceled Wednesday's edition.
The last major hurricane to hit the area was Heta, which plowed through American Samoa and neighboring Samoa in January 2004 with wind gusting to 200 mph.
Heta damaged more than 4,600 homes in American Samoa, according to the American Red Cross. It also devastated up to 90 percent of the crops on Samoa.
American Samoa, in the South Pacific, is the United States' southernmost territory.