U.S. Secretary of State John Kerry plans to travel to Moscow next week for talks with Russian Vladimir Putin about the drawdown and the new push for peace in Syria.
Kerry said he would talk with both Putin and Foreign Minister Sergei Lavrov about how to move forward with the process of bringing a political solution to the five-year conflict.
Fighting in Syria has drastically declined with a cessation of hostilities in place for about three weeks.
But Kerry also warned that lasting peace is impossible if Syrian President Bashar al-Assad remains in power.
The first Russian troops to leave Syria arrived back home Tuesday to cheering crowds.
Putin made the surprise announcement Monday that the bulk of his forces will leave now that they have achieved their mission in Syria, which began in late September.