Obama's Libyan challenge
President Barack Obama has condemned the "outrageous attack" which killed the American ambassador in Libya and three others.
He says their service "exemplified America's commitment to freedom, justice and partnership with nations and people around the globe, and stand in stark contrast to those who callously took their lives".
The ambassador and the others were killed in an attack by people who believed an American had made a film insulting Islam.
The president has ordered stepped-up security around the world and added: "While the United States rejects efforts to denigrate the religious beliefs of others, we must all unequivocally oppose the kind of senseless violence that took the lives of these public servants."
It is almost inevitable that this attack will put President Obama's foreign policy centre stage in the election campaign, at least for a while.
Opponents of President Obama have portrayed him as too willing to apologise for America around the world, and too sympathetic to Islam. Others suggest support for the Arab Spring has allowed those hostile to America to become more powerful.
Republican presidential nominee Mitt Romney's campaign earlier reacted to a statement put out by the US embassy in Cairo condemning attempts to hurt Muslims' religious feelings. That embassy had also come under attack.
Mr Romney said: "It's disgraceful that the Obama administration's first response was not to condemn attacks on our diplomatic missions, but to sympathise with those who waged the attacks".
The White House said that the original statement had not been approved by them.
The attack is also likely to prompt a debate about President's Obama's support for Nato's military campaign, which led to the downfall of Colonel Gaddafi.
At the time, Mr Romney accused the president of dithering, but didn't say whether he was doing too much or too little.