Violence in the post-Arab Spring Middle East threatened to upset the presidential race Wednesday after the U.S. ambassador to Libya and three other staffers were killed in an attack by an angry mob on the U.S. consulate in Benghazi.

Ambassador Christopher Stevens, two security officials and another consulate worker were killed as they tried to evacuate the burning building set aflame by protesters.

Initial reports attributed the attack to anger over a crude anti-Islam Web video that mocked the religion. But Obama administration officials now suspect the attack on the consulate was planned, according to The New York Times, though the intelligence is inconclusive.

President Obama and lawmakers on Capitol Hill in both parties condemned the attacks, but GOP presidential nominee Mitt Romney struck a different note by ripping the Obama administration’s response and criticizing the president’s handling of foreign policy.