The two senators leading Congress's Fort Hood investigation on Monday subpoenaed the Obama administration for documents and witnesses that the Pentagon has refused to provide.
The administration is wary of allowing Sens. Joe Lieberman and Susan Collins open access to front-line agents in their investigation into the Fort Hood shootings, which left 13 people dead.
A report released Friday on the Fort Hood shootings was short on specifics about Army officers who failed to do their jobs. But the Army is conducting another investigation, which could result in disciplinary action.
The Pentagon review will recommend disciplinary action if it finds individuals failed to do their job in the run up to Fort Hood shootings, officials say. The alleged shooter is an Army psychiatrist who reportedly exhibited some troubling behavior.