Mohdar Mohamed Abdoulah, 24, a former San Diego State University student, also helped the men obtain California drivers' licenses and Social Security cards, federal prosecutors said.
FBI agents arrested Abdoulah less than two weeks after the Sept. 11 attacks and held him as a material witness in the terror investigation.
Prosecutors said Abdoulah assisted Khalid Almihdhar and Nawaf Alhazmi, who are suspected of hijacking American Airlines Flight 77 and crashing it into the Pentagon.
The men lived in San Diego for several months in 2000. Prosecutors also describe a third Flight 77 hijacker, Hani Hanjour, as Abdoulah's friend.
Abdoulah is accused of filing an asylum application in May 2000 in which he falsely claimed he was from Somalia and a member of a minority group that faced persecution there. He is being held on $500,000 bail.
After his arrest, Abdoulah spoke without prompting of "the hatred in his heart for the United States government, and that the United States brought 'this' on themselves," prosecutors wrote.
The documents were filed Monday in response to a request by defense attorneys to dismiss Abdoulah's immigration-fraud charges. The defense request remains sealed.
Federal agents who interviewed Abdoulah said they didn't believe his denials of advance knowledge of the attacks, prosecutors said. Abdoulah "seemed to take great pleasure toying with the agents and schooling them on Islam and jihads," according to the court document.
A spiral notebook found in Abdoulah's car "contained references to planes falling from the sky, mass killings and hijacking," prosecutors said. The writings also refer to "burning flesh falling from the sky."
Abdoulah's attorney, Kerry L. Steigerwalt, said the writings were "rap lyrics" penned after Sept. 11 by a teen-ager who left the notebook in his client's car.
While he did help Almihdhar and Alhazmi, the lawyer said "that's not to imply or suggest that he had any indication whatsoever that these people were as radical as they were or ... they could possibly be contemplating or planning such a horrific attack."
In court papers, U.S. Attorney Michael Wheat described as "pure speculation" defense arguments that the writings were not Abdoulah's. Wheat did not return a phone message seeking comment Wednesday.
By Seth Hettena