Friday's attacks in Paris have cast a shadow over the Group of 20 summit, which opened Sunday in Antalya, in southern Turkey. Leaders of 20 major economies agreed to step up the battle against ISIS and to ease the wider conflict in Syria.
After a moment of silence for the victims in Paris, Turkish President Recep Tayyip Erdogan told everyone gathered that terrorism threatens everyone. He raised concerns about the refugee crisis flowing from the Syrian civil war and said the world has not passed that exam with good grades.
President Obama reassured his host that the U.S. will do more to find a solution to Syria's political crisis, while at the same time countering ISIS, known by its Arabic acronym, Daesh.
"We will redouble our efforts working with other members of the coalition to bring about a peaceful transition in Syria and eliminate Daesh as a force that can create so much pain and suffering in Paris, in Ankara and other parts of the globe," Obama said.
At one point at the G-20 summit, Obama was seen huddling with Russian President Vladimir Putin, whose military is propping up President Bashar Assad's regime in Syria. The White House called the 35-minute discussion productive.
In the past, Obama has dismissed Russia's intervention as a mistake and has made clear that the war in Syria won't end as long as Assad is in power. Despite the differences, Putin called for a more coordinated international approach.
"We all understand perfectly well that dealing with the terrorist threat and helping millions of people who have lost their homes is only possible by combining all our efforts," Putin said.
For now, the U.S. and Russia have agreed to disagree over Assad's fate. And that disagreement was on display when Secretary of State John Kerry met in Vienna with his Russian counterpart, Sergei Lavrov. The two agreed on a diplomatic plan that calls for a cease-fire.
United Nations Secretary-General Ban Ki-moon saw this as a hopeful sign on Sunday.
"After years of division, this is a rare moment of diplomatic opportunity to end the violence and advance the possibility of a political solution," he said.
Daniel Gorevan, a Syria expert with the humanitarian agency Oxfam, is in Antalya to keep the world focused on the crisis in Syria. He says he is heartened by the Vienna agreement.
"If the provisions in that statement — so, a monitored cease-fire, an end to indiscriminate attacks and access to besieged areas, that would bring respite and relief to millions of civilians," Gorevan said.
There is a danger, though, that — like other failed attempts to resolve the war in Syria — these promises will remain on paper only. Gorevan urged the powers meeting here to make a concerted effort this time, and to do more to end the worst refugee crisis since World War II.
"There needs to be a new deal between the rich countries to provide ... that financing to neighboring countries," he said, "and the neighboring countries need themselves to open up that space for refugees to live legally and in dignity, so that they can support themselves."
The Paris terrorist attacks have added a sense of urgency, though the Oxfam activist says the humanitarian disaster emanating from Syria should have already been enough for this crisis to rise to the top of the world's agenda.