A chilly mood prevailed between President Obama and Russian President Vladimir Putin when they gathered for bilateral talks at the G-8 Summit.
The two men are on opposite sides in the Syrian conflict. Putin supports Syrian President Bashar al-Assad and doesn't believe he should step aside.
On the opposite side is Obama, who decided last week to send small arms to rebel forces fighting to overthrow the Syrian president.
"What developed over several months was high confidence that the Assad regime had used chemical weapons," the president said in an interview with Charlie Rose that aired on PBS Monday evening.
"And I had been very clear, that if we saw the use of chemical weapons taking place by the regime inside of Syria, that would change my calculus. And it has," the president said.
But Putin believes the evidence is questionable. He opposes U.S. intervention in Syria and said the Russian and U.S. positions "do not coincide, but all of us have the intention to stop the violence in Syria."
While Obama and Putin agree to disagree on Syria, both support attempts to bring the two sides in Syria's 26-month civil war to peace negotiations to end the conflict.
Arranging that is proving difficult.The rebels want Assad to step aside before talks begin. Assad and Russia refuse.
Other members of the G-8 were critical of Putin for supporting the Syrian dictator. One British official described the summit as a "clarifying moment in differences over Syria."
When criticized for sending Russian arms to the Assad regime, Putin responded that the shipments were to "the legitimate government of Syria, legal under international law."
British Prime Minister David Cameron, G-8 Summit host, tried to emphasize areas of agreement.
"It is no secret that President Putin and I have had our disagreements," Cameron said. "We share some fundamental aims to end the conflict, to stop Syria breaking apart."
The G-8 meeting will conclude with members sending a clear message: When it comes to Syria, the G-8 is really the G-7 plus one -- Russia, which stands alone in its support of the Syrian government and Bashar al-Assad.