Secretary of State John Kerry and Foreign Minister Sergey V. Lavrov of Russia stood, their heads bowed, for a moment of silence Friday morning for those who died Thursday night in the attack in Nice, France.
“I believe this dialogue is becoming even more relevant and urgent because of Nice,” Mr. Lavrov said, referring to talks between the United States and Russia.
The two men, who are negotiating details of a possible military-cooperation agreement in Syria to fight Al Qaeda, Islamic State militants and their affiliates in Syria, both expressed abhorrence at the attack. Mr. Kerry met with President Vladimir V. Putin of Russia until 1 a.m. Friday.
Mr. Kerry said that Syria had become the incubator for attacks like the one in Nice, saying: “You and I and our teams are in the enviable position of actually being able to do something about it.”
He described the conversations so far as “very fruitful and very serious” and said they had included issues beyond Syria, including the Israeli-Palestinian conflict, fighting in Yemen and Russia’s continuing support for separatists in Ukraine.