President Barack Obama told the United Nations today, amid a U.S.-led bombing campaign against ISIS militants, that he will build a coalition to "dismantle this network of death."

Obama told the assembled leaders on Wednesday that the "only language understood by killers like this is the language of force." The president warned those who have joined the Islamic State in Iraq and Syria to "leave the battlefield while they can."

After weeks of launching strikes against militant targets in Iraq, Obama extended the military action into Syria on Monday. The U.S. was joined by a coalition of five Arab nations.

He told the UN that ISIS has terrorized all they come across in Iraq and Syria. He referred to rape as their weapon of war, starvation, and televised beheadings.

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President Barack Obama is shown Tuesday night in New York, speaking at the Clinton Global Initiative. (Pablo Martinez Monsivais/The Associated Press)

"No God condones this terror. No grievance justifies these actions. There can be no reasoning – no negotiation – with this brand of evil," Obama said.

The only language understood by killers like this is the language of force. So the United States of America will work with a broad coalition to dismantle this network of death."