US President Barack Obama and Russian President Vladimir have agreed on the first steps towards peace in Syria.
The horror of the attacks in Paris shook leaders at the G20 summit in Turkey, adding a new urgency to their search for a solution to the four-year war in Syria that has enabled the rise of Islamic State jihadists.
Putting aside important differences, Obama and Putin met over a coffee table on the sidelines of the Group of 20 summit in the resort of Antalya to align their positions on Syria after the Paris assaults, which killed at least 129 people and were claimed by IS.
"The conversation lasted approximately 35 minutes and centred around ongoing efforts to resolve the conflict in Syria, an imperative made all the more urgent by the horrifying terrorist attacks in Paris," a US official said on Sunday.
Obama and Putin agreed on the need for United Nations talks, a ceasefire and a transition government in Syria, the US official said, echoing a plan for Syria already forged by diplomats at talks in Vienna the previous day.
The Kremlin said "divergences" remained on tactics even if they shared the same goal against Islamic State.
It was the two presidents' first meeting since Russia in September launched an air campaign in Syria which the Kremlin insists is aimed against IS jihadists.
The West however suspects Moscow's true aim is to target opponents of Syrian President Bashar al-Assad.
In images captured on Turkish public television, Putin and Obama were seen hunching towards each other as they held animated talks, in stark contrast to the frigid body language that marked previous meetings.
The Paris attacks on Friday darkened the mood and injected urgency into anti-terrorism discussions at the G20 summit, which is also grappling with the spreading refugee crisis, climate change and tax avoidance by multinational corporations.
In a draft special statement obtained by AFP a day before its formal adoption, world leaders raised the alarm over an "acute and growing flow of foreign terrorist fighters".
They vowed to share intelligence, track border crossings and boost aviation security to halt the movement of jihadist fighters.