WASHINGTON (AP) - An independent investigation into the deadly Sept. 11 attack on the U.S. diplomatic mission in Benghazi, Libya, is complete, and Congress will be briefed on its findings this week, the State Department said Monday.

The classified report by the Accountability Review Board will be sent to Capitol Hill on Tuesday, a day before the panel's two most senior members will testify in closed session before the House and Senate foreign affairs committees. The board was established to examine the attack that killed U.S. Ambassador to Libya Chris Stevens and three other Americans.

The House Foreign Affairs and Senate Foreign Relations committees will then hear open testimony on the report on Thursday from William Burns and Thomas Nides, Secretary of State Hillary Rodham Clinton's two main deputies, Nuland said.