Updated

WASHINGTON (AP) — The Obama administration said Tuesday it will provide some but not all the materials a Senate committee wants on last year's Fort Hood shooting rampage, setting up a potential legal showdown with Congress.

The Senate Homeland Security and Governmental Affairs Committee had demanded that the Pentagon share documents and witnesses about the deadly incident by Tuesday morning.

An unusual Senate subpoena sought material the Pentagon claims would jeopardize prosecution of the suspect, Major Nidal Hasan. The U.S. Army psychiatrist has been accused of killing 13 people in November at Fort Hood, Texas.

Senators have said they want to be sure the Pentagon is working to prevent similar tragedies.

Committee spokeswoman Leslie Phillips said that "as far as we're concerned they have not complied with the subpoena." She said the panel is considering its next step.

The Pentagon and Justice Department sent a letter to the committee Tuesday morning that Pentagon press secretary Geoff Morrell said lays out a compromise.

The committee would be able to read Hasan's personnel file and a secret addendum to the Pentagon's internal report on how the Pentagon failed to head off the shootings despite concerns over Hasan's behavior and apparent religious radicalization.

The committee would not be given access to witnesses in the case or to investigative reports that could be used at trial, Morrell said.

The administration also refused to let the committee have copies of the file and secret addendum because their release might jeopardize Hasan's prosecution.

"We have made a very good faith effort to try to find a middle ground," Morrell said.

The administration also offered additional briefings to select senators about the activities of an anti-terrorism task force that reviewed tips about Hasan.

"This is as far as we're prepared to go," Morrell said.