The White House is facing tough questions after the administration failed to comply with a key legal requirement while securing the release of Army Sgt. Bowe Bergdahl.

Section 1033 of the 2014 National Defense Authorization Act requires the president to notify Congress 30 days prior to the release of detainees from Guantanamo Bay. Lawmakers say they were not notified of the release of five Taliban leaders exchanged by the U.S. government for Bergdahl. Sen. Lindsey Graham, R-S.C., sent a letter to Armed Services Committee Chairman Carl Levin on Monday, requesting an immediate hearing to determine whether any laws were broken.

National security adviser Susan Rice defended the decision on Sunday, telling CNN the "acute urgency" of the situation necessitated a rapid response from the administration. The remarks were reiterated on Monday by White House Chief of Staff Denis McDonough, who insisted Congress had known about the negotiations with the Taliban for years. He also said lawmakers were aware a prisoner exchange was a possible eventuality.

At Monday's press briefing, White House spokesman Jay Carney joined other administration officials in refusing to specify why the president felt securing Bergdahl's release was an urgent matter. Bergdahl had been held in Taliban captivity for more than five years.