President Barack Obama, speaking in the UN General Assembly, vowed that the US “would do what it must” to stop Iran’s nuclear ambitions despite UN Secretary-General Ban Ki Moon’s warning against “threatening attacks”, AFP reports.

Addressing the crises in the Middle East resonated in the first day of the session, with world leaders appealing to put an end to the relentless violence in Syria and Iran’s nuclear expansion. UN Secretary-General Ban Ki Moon strongly condemned the ongoing civil war in Syria, calling it “a serious and growing threat to international peace and security”. Mr. Ban urged on a “Security Council action” which is at a deadlock after Russia and China vetoed sanctions against Syria.

Mr. Ban went on to call for the body to reject threats of military action, saying that the consequences of such attacks would be “devastating”.

Mr. Obama’s remarks, however, had an undertone of a warning. “A nuclear-armed Iran is not a challenge that can be contained. It would threaten the elimination of Israel, the security of Gulf nations, and the stability of the global economy,” Mr. Obama said. “That is why a coalition of countries is holding the Iranian government accountable. And that is why the United States will do what we must to prevent Iran from obtaining nuclear weapon”.

Mr. Obama’s speech laid out  “a vision of American leadership” in the face of unrest in the Muslim world fueled by a ‘crude’ film mocking the Prophet Mohammed.