U.S. President Barack Obama and Russian President Vladimir Putin clashed sharply Monday at the United Nations on how to end four years of fighting in Syria.

Ahead of a face-to-face meeting between the two world leaders set for later in the day, Obama told the annual U.N. General Assembly gathering that after so much bloodshed and carnage, Syria cannot return to a pre-war status quo. He called for a "managed transition" to oust Syrian President Bashar al-Assad.

But Putin, making his first U.N. speech in a decade, warned that it would be an "enormous mistake" to not cooperate with the Assad government in fighting Islamic State insurgents trying to oust the Syrian leader. He called for a "broad coalition" to combat Islamic State fighters, much like the "anti-Hitler" alliance that fought together in World War Two.

Obama said there were "no simple answers" for the fighting in Syria, but said diplomacy must be used to "forge an agreement (for the Syrian people) to live together peacefully." He denounced Assad as a leader "who drops barrel bombs on his people... an assault on all our humanity."

"Catastrophes like in Syria do not take place in countries where there is "genuine democracy," Obama added.

The U.S. leader called on the world to shun war and conflict and instead engage in new diplomatic efforts to resolve conflicts across the globe.

"If we cannot work together cooperatively," Obama said, "we will all suffer the consequences. We will all be stronger when we work together."

Yet Obama also defended U.S. military strength and the U.S. campaign against Islamic State insurgents in Syria and Iraq. He said the Islamic State would never have a "safe haven."

He criticized Russia for its annexation a year ago of Ukraine's Crimea peninsula and involvement in support of pro-Russian separatists in eastern Ukraine. He said Western economic sanctions against Moscow were necessary because no country could overlook the Crimean takeover "with impunity."

"If that happens without consequences in Ukraine, it could happen to any nation gathered here today," Obama said.

Obama administration officials have repeatedly said that a political transition cannot occur in Syria as long as Assad remains in power. That issue is expected to be a focus of the Obama-Putin meeting, their first formal talks since the June 2013 G-8 summit. It comes at the repeated request of Moscow, according to White House Press Secretary Josh Earnest. It also comes amid U.S. concerns about Russia expanding its military presence in Syria.

“President Obama will make clear once again that Russia doubling down on their support for the Assad regime is a losing bet,” Earnest told reporters last week.

In the U.N. speech, Obama said it "not weakness, but strength" when world leaders trust people in their countries and open the path to democracy.

"History shows that countries that ignore their people will eventually crumble," he said.

Obama singled out the recently completed international accord blocking Iran from building a nuclear weapon as an example of how diplomacy can work, when nations are held accountable for violating international rules. (Source: VOA News)

Story Date: September 29, 2015