Russia and the United States are sponsors of an international effort to broker a ceasefire and political talks between Bashar al-Assad's regime and Syria's armed opposition.
But their positions on Assad's eventual fate and the best tactics to employ against the jihadist Islamic State group differ starkly, threatening to stymie the process.
Kerry came to Moscow on Tuesday not even knowing whether Russia would agree that the next international meeting on the crisis should take place on Friday in New York.
"I am very happy to have the opportunity to meet and talk with you," Putin said, sitting beside his foreign minister, Sergei Lavrov, who had met Kerry earlier in the day.
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"Minister Lavrov just now informed me in detail about both your proposals as well as some issues which require additional discussions," Putin added.
Kerry said that he hoped to address the crises both in Syria and in Ukraine, where Washington accuses Moscow of backing separatist rebels and has imposed sanctions on Russia.
"Both you and President Obama have committed themselves to trying to develop as much as possible ... An approach that can try to deal with Ukraine and deal with Syria," Kerry said.
"So I very much look forward to our discussion now and appreciate the seriousness of your commitment of time and thought about these issues," he added.
Then the press was ushered out, and the talks began in earnest.
Speaking after meeting Lavrov, Kerry declined to say whether the New York negotiations would go ahead on Friday.
"Well, I need to meet with the president," he told reporters on a stroll in central Moscow, where he was mobbed by Russians wanting to meet Washington's top diplomat.
Washington is relying on the Kremlin to drag Russian ally Bashar al-Assad to the table for talks with his rebel opponents on ending Syria's vicious four-and-a-half-year-old civil war.