Obama vows to keep up military pressure on Islamic State

US President Barack Obama vowed at the United Nations on Wednesday to keep up the military pressure on Islamic State militants and urged those who have joined the extremist group in Iraq and Syria to "leave the battlefield while they can."

Speaking at the UN General Assembly, Obama said Islamic State must be destroyed and issued a global call for nations to come together to join a US-led coalition. Before he spoke, US-led airstrikes for the third time this week pounded Islamic State targets in Syria and Iraq.

"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," he said in his speech, which ran to just under 40 minutes.

He added that the United States does not intend to occupy any countries, but "will support Iraqis and Syrians fighting to reclaim their communities."

Obama used his annual address to the 193-nation General Assembly to send messages to Russia to back down from its aggression against Ukraine, for Iran to "not let this opportunity pass" to forge a nuclear deal and, indirectly, for China to ease its pressure on its Asia-Pacific neighbors.

But his over-arching message was that Islamic State, a group whose rapid rise and seizure of broad swaths of Syria and Iran has stunned the Middle East, was of concern to the West and had prompted five Arab states to join the United States in military strikes.

He referred to Islamic State by the acronym ISIL.

"Today, I ask the world to join in this effort. Those who have joined ISIL should leave the battlefield while they can," he said. "We will not succumb to threats."

Obama said a peaceful conclusion to Syria's three-year-old civil war must be found and that a broader peace is needed in the Middle East.

"It's time for a broader negotiation in which major powers address their differences directly, honestly, and peacefully across the table from one another, rather than through gun-wielding proxies," he said.

On the Israeli-Palestinian dispute specifically, Obama said the violence engulfing the region has made too many Israelis "ready to abandon the hard work of peace."

"But let's be clear: the status quo in the West Bank and Gaza is not sustainable. We cannot afford to turn away from this effort," he said.

On Ukraine, Obama said that if Russia takes the path of peace and diplomacy, then the United States would lift its economic sanctions and would be prepared to engage in the type of diplomacy that in the past has reduced U.S. and Russian nuclear stockpiles and persuaded Syria to give up chemical weapons.

"That's the kind of cooperation we are prepared to pursue again if Russia changes course," he said.

On Iran, Obama said there remains an opportunity to reach an agreement between Tehran and world powers aimed at resolving long-standing differences over Iran's nuclear program.

"My message to Iran's leaders and people is simple: do not let this opportunity pass. We can reach a solution that meets your energy needs while assuring the world that your program is peaceful," he said.

He urged countries in the Asia-Pacific, without mentioning China in particular, to resolve their differences in the region peacefully and along the norms of international law.

He also called for many more countries to make concrete commitments to fight the deadly Ebola outbreak in West Africa.