According to official reports, a U. S. Senate subcommittee Monday subpoenaed Attorney General Eric Holder and Defense Secretary Robert Gates to testify about the Fort Hood, Texas, shooting.

ABC News has reported that the subpoenas, to appear before the Senate Homeland Security Committee April 27, were issued by Chairman Joe Lieberman, Ind-Conn., and Sen. Susan Collins, R-Maine, the ranking Republican on the committee.

It was further reported that Lieberman and Collins want to compel the two Cabinet members to tell lawmakers what the federal government knew about Army Maj. Nidal Hasan, the accused Fort Hood shooter, before the Nov. 5 incident that left 13 people dead and about 30 wounded.

The U. S. network said that Lieberman and Collins said they resorted to the subpoenas because the Obama administration was dragging its feet.

The letter had said, "We have repeatedly sought your departments' cooperation for more than five months. Our efforts have been met with delay, the production of little that was not already publicly available and shifting reasons for why the departments are withholding the documents and witnesses that we have requested."

He wanted to learn what information the government had about Hasan's contacts with radical Muslim cleric Anwar Awlaki, Lieberman has said.

The subpoenas demand information on contacts between Hasan and Awlaki in the months before the shooting spree.

The letter asks, "Given the warning signs about Maj. Nidal Malik Hasan's extremist radicalism, why he was not stopped before he took thirteen American lives?"

It's not a matter of the administration hiding information from Congress but making sure nothing is done to negatively impact Hasan's prosecution, Gates has said. (With Inputs from Agencies)