WASHINGTON — The Obama administration will probably soon release at least part of a 28-page secret chapter from a congressional inquiry into the 9/11 terrorist attacks that may shed light on possible Saudi connections to the attackers.

The documents, kept in a secure room in the basement of the Capitol, contain information from the joint congressional inquiry into ‘‘specific sources of foreign support for some of the Sept. 11 hijackers while they were in the United States.’’

Bob Graham, who was cochairman of that bipartisan panel, and others say the documents point suspicion at the Saudis. The former Democratic senator from Florida said an administration official told him that intelligence officials will decide in the next several weeks whether to release at least parts of the documents.

‘‘I hope that decision is to honor the American people and make it available,’’ Graham told NBC’s ‘‘Meet the Press’’ on Sunday. ‘‘The most important unanswered question of 9/11 is, did these 19 people conduct this very sophisticated plot alone, or were they supported?’’

Fifteen of the 19 hijackers were citizens of Saudi Arabia. The Saudi government says it has been ‘‘wrongfully and morbidly accused of complicity’’ in the attacks, is fighting extremists and working to clamp down on their funding channels.

The pages were withheld from the 838-page report on the orders of President George W. Bush, who said the release could divulge intelligence sources and methods.