A mob armed with guns and grenades launched a fiery attack on the U.S. Consulate, killing the U.S. ambassador to Libya Chris Stevens and three other Americans on Sept. 11, 2012. President Barack Obama strongly condemned the violence and vowed to bring the killers to justice and tightened security at diplomatic posts around the world.

On. Jan. 23, 2013, in her last formal testimony on Capitol Hill as America's top diplomat, Secretary of State Hillary Rodham Clinton took full responsibility for the department's missteps leading up to an assault.

Clinton said the department is implementing the 29 recommendations of an independent review board that harshly criticized the department as well as going above and beyond the proposals, with a special focus on high-threat posts.- AP