"The attacks on our civilians in Benghazi were attacks on America. There should be no doubt that we will be relentless in tracking down the killers and bringing them to justice," Obama told the UN General Assembly.
But while eulogising US ambassador Christopher Stevens, who was killed two weeks ago along with three other Americans, Obama also styled the attack as not just an assault on America, but also on the ideals behind the United Nations.
"Today, we must affirm that our future will be determined by people like Chris Stevens, and not by his killers. Today, we must declare that this violence and intolerance has no place among our United Nations."
In his annual speech to the world body, Obama again condemned the video produced by Coptic Christian extremists in the United States that set violence raging across the Arab world as "crude and disgusting."
But he said that however vile, no exercise of free speech that is protected by the US Constitution could justify killing and violence.
"Here in the United States, countless publications provoke offense. Like me, the majority of Americans are Christian, and yet we do not ban blasphemy against our most sacred beliefs.
"Moreover, as president of our country, and commander-in-chief of our military, I accept that people are going to call me awful things every day, and I will always defend their right to do so."
Obama also warned that in 2012 "when anyone with a cell phone can spread offensive views around the world with the click of a button, the notion that we can control the flow of information is obsolete."
"The question, then, is how we respond. And on this we must agree: there is no speech that justifies mindless violence."
"There are no words that excuse the killing of innocents. There is no video that justifies an attack on an embassy."
Obama also demanded "sanctions and consequences" for atrocities in Syria and said President Bashar al-Assad's rule must come to an end.
"The future must not belong to a dictator who massacres his people," Obama told the UN General Assembly in a keynote address.
"If there is a cause that cries out for protest in the world today, it is a regime that tortures children and shoots rockets at apartment buildings."
He told leaders at the UN headquarters: "As we meet here, we again declare that the regime of Bashar al-Assad must come to an end so that the suffering of the Syrian people can stop, and a new dawn can begin."
Obama also warned that the international community must act to prevent the 18 month old uprising against Assad turning into "a cycle of sectarian violence."
He said the United States wants a Syria "that is united and inclusive; where children don't need to fear their own government, and all Syrians have a say in how they are governed – Sunnis and Alawites; Kurds and Christians."
"That is the outcome that we will work for – with sanctions and consequences for those who persecute; and assistance and support for those who work for this common good," Obama said.
"We believe that the Syrians who embrace this vision will have the strength and legitimacy to lead."
Ban Ki-moon
UN leader Ban Ki-moon on Tuesday condemned "shrill" talk of war between Israel and Iran which he said would be devastating.
Without mentioning the two rivals by name, Ban told the start of the UN General Assembly that he rejects "threats of potential military action by one state against another.
"Any such attacks would be devastating. The shrill war talk of recent weeks has been alarming," he told the 193-nation assembly where the showdown over Iran's nuclear program is one of the dominant themes.
Iran's President Mahmoud Ahmadinejad, who is in New York, has shrugged off talk of an Israeli attack on his country's nuclear facilities. But US President Barack Obama was to warn that the United States would "do what we must" to stop Iran getting a nuclear weapon.
Iran has denied western accusations that it seeks a nuclear bomb.
Ban said that the Syrian civil war is a "calamity" that now threatens world peace and demands action by the divided UN Security Council.
Ban said that the Syria conflict "is a regional calamity with global ramifications" that needs action by the Security Council.
"The international community should not look the other way as violence spirals out of control," Ban told world leaders, adding that "brutal" rights abuses were being committed by President Bashar al-Assad's government.
"I call on the international community – especially the members of the Security Council and countries in the region – to solidly and concretely support the efforts" of UN-Arab League envoy Lakhdar Brahimi.
"We must stop the violence and flow of arms to both sides and set in motion a Syrian-led transition as soon as possible," Ban added.
The 15-nation Security Council has become paralyzed by deadlock over the 18-month-old deadlock which Syrian activists say has left more than 29,000 dead.
Russia, Assad's main ally, and China have vetoed three Security Council resolutions which could have led to sanctions against the Syrian government.
Ban said the crimes being committed in Syria must not go unpunished. "There is no statute of limitations for such extreme violence," he insisted.
"It is the duty of our generation to put an end to impunity for international crimes in Syria and elsewhere."
Ban said he wanted his address to the 193-member UN to "sound the alarm about our direction as a human family."
COMMENTS (16)
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Headline: Obama vows to hunt killers of US ambassador to Libya
What does this mean? Their future invitations to diner are cancelled. Hisham Y. Altalib is not happy!
There is hardly a 'Muslim Ummah' left ! 'Muslims' of the world have forgotten their Allah and his teachings, they have ridiculed and abused the faiths of others against the teachings of Allah. They are already slitting each others throats across the world and in my opinion in the middle of the worst period after Halaku Khan obliterated them in 1257.
@Atheist: Oh Please! A brave President would not have referred to the video so many times and would have set boundaries firmly with the dark side that either you grow up or you will destroy your own society by getting lost in your own darkness.
@sincere: The rule of the civilised world is "might is right". The have have nothing to with logic and rational thnking. The Muslim Ummah is in a state of coma. The only way to counter American-Israel disinformation is that the Muslim Ummah should launch a cyber-jehad.
@Jaideep Gupta
Rubbish. If you look beyond the news published solely in Pakistan you will discover that the people of Libya rose up and attacked the Muslim militants who claimed responsibility for this murder tossing them out of their military encampments & apologizing to the American's. Both the Libyan govt and it's people don't want their country to devolve into another Pakistan with militant groups running amok.
By far the bravest and smartest president US ever had...
Mr. Obama ,please take out the person who you have taken out a bounty of US$10million. It will save the world
The killers of ambassder must be punished at any cost . The speech of Pak representative should be scrutinized in this regard . He should not be allowed to misuse the world plateform .
Now it is really a very bad news for Libyans. Actually US has threatened to take action against Libya.We have seen that they have done same in Pakistan and Afganistan.
And if the Coptic Christian film producer is murdered your Minister of Railroads will discover that one of the consequences of placing his bounty is that he will be charged with the crime of murder in the USA. If he travels outside of Pakistan chances are he will be arrested and eventually extradited to the USA where he will spent the rest of his life in a jail cell.
Community organizer cum assassin in chief directly responsible for killing thousands of innocents civilians with his drones has spoken against violence.
Killing and thinking about it for healthy mind is sin. Having Nuk or developing it is job of devil, because devil ordered for war, God asking for PEACE everywhere anytime. If Mankind thinks about after dead, never ever going have chance to look to bad thing.
While hunting down of killer of US ambassador Christopher Stevens is good step but Obama should also do some prevention of potential violence by adding Railways minister Ghulam Ahmed Bilour on the No fly list, Interpol red corner notice and extradite him to USA for conspiracy to murder and attempt to hire to harm a lawful citizen of USA.
Security council has to take action on the basis of existing ground realities in case of all pending cases at once to ensure the world peace for the future genrations . The action can be unilateral if needed in some cases .
don't allow the entry of those who don't listen you , Mr Ban
America can make thousands of nuclear bombs, Israel has made more than 50 nuclear bombs but Iran can not do this. what kind of logic is this. It means simply to accept the slavery of America & Israel. I wounder why the Muslim umma is not debating these points. Now a days the war is fought on media, inspite of the reasons that America & Israel are totally wrong on nuclear issue they are showing on media that they are right. may God give some wisdom to Muslims.