Amid mounting unrest in the Middle East, President Obama today warned Iran that the time for diplomacy is running out and challenged global leaders to confront the "deeper causes" of the crises, saying the turmoil serves as a reminder that true democracy is "hard work."

"We face a choice between the forces that would drive us apart, and the hopes we hold in common," the president told the United Nations General Assembly.

"The attacks of the last two weeks are not simply an assault on America," he argued. "They are also an assault on the very ideals upon which the United Nations was founded - the notion that people can resolve their differences peacefully; that diplomacy can take the place of war; and that in an interdependent world, all of us have a stake in working towards greater opportunity and security for our citizens."

Two years after the start of the Arab Spring and six weeks before U.S. elections, the president insisted "progress" has been made, but made clear "democracy does not end with the casting of a ballot."

"True democracy - real freedom - is hard work," he said.

Transcript: President Obama's remarks at the U.N.

"True democracy demands that citizens cannot be thrown in jail because of what they believe, and businesses can be opened without paying a bribe. It depends on the freedom of citizens to speak their minds and assemble without fear; on the rule of law and due process that guarantees the rights of all people," he said.

Read more about the speech before the U.N. and Obama's pledge on Iran.