The hope is that a deal will lead to a cessation of hostilities across Syria and relaunch talks on a political transition in the country.
While Kerry said this week that technical teams from both sides were close to the end of their discussions, U.S. officials indicated it was too early to say whether a deal was likely.
When Kerry launched the Syrian cooperation talks in July on a visit to Moscow, the proposal involved Washington and Moscow sharing intelligence to coordinate air strikes against Islamic State and grounding the Syrian air force to stop it from attacking moderate rebel groups.
Russia agreed to a 48-hour humanitarian ceasefire in the divided Syrian city of Aleppo to allow aid deliveries, although U.N. officials said they were waiting for security guarantees from parties on the ground.
The United Nations has pushed for a weekly pause in the fighting in Aleppo to deliver food, water and medicine to people caught in the fighting.
Separately, Syrian rebels and government forces agreed in a deal on Thursday to evacuate all residents and insurgents from the besieged Damascus suburb of Daraya, ending one of the longest standoffs in the five-year conflict.
