Russia's defense ministry said more of its planes left Syria Wednesday, continuing its withdrawal as the U.N. held more indirect peace talks with Syria's warring sides in Geneva.
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 the war-torn country.
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.
"This is a moment to seize, not waste," he said Tuesday. "We have at this moment the ability to finally take steps toward ending war and bloodshed."
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.
White House spokesman Josh Earnest told reporters Tuesday that early indications were that Russia was following through on Putin's order.
At the U.N.-led peace talks in Geneva, the main Syrian opposition cautiously greeted the withdrawal, saying it could lead to the end of the conflict and Assad's "dictatorship and his crimes."
The U.N. special envoy for Syria, Staffan de Mistura, called Putin's announcement a "significant development" and said he hopes it will lead to "a peaceful political transition in the country."
France also expressed cautious optimism, with its foreign ministry saying that if the Russian troop reduction is "followed up by concrete action, it would be a positive development."
Despite the initial withdrawal, Russia plans to keep about 1,000 military personnel at air and naval bases in Syria. The United States has estimated that Moscow has had between 3,000 and 6,000 troops in Syria.
In Syria, deputy defense minister Nikolai Pankov told Russian news agencies, "It is still too early to speak of victory over terrorism. The Russian air group has a task of continuing to strike terrorist targets."
VOA State Department correspondent Pam Dockins contributed to this report.