The state secretary referred to US contacts with opposition and militants still encircled by Syrian government forces in Aleppo on ending violence in the city and withdrawing Jabhat Fatah al Sham (formerly al-Nusra Front) militants from the opposition-controlled areas.
Kerry stressed that the end of the battle for Aleppo would not spell an end of the Syrian conflict and that a political solution via international diplomacy is still necessary.
"We are prepared to accept a negotiation in which there is a transition. Assad is part of that transition. Ultimately, there is an election and the people of Syria make a decision about the future leadership of their country," he told the audience.
The comments come just hours after the Russian Defense Ministry announced that the Syrian army had liberated over half of militant-held areas of Aleppo during the latest week-long offensive in the war-torn city.
In late November, Syrian government forces, supported by local militias, launched a large-scale offensive against extremist groups in the eastern part of Aleppo.
On Saturday, militants still encircled in the city again refused to seize the government offer of safe passage out of the city and vowed to continue resistance.
Over recent months, Aleppo became major battleground in Syria, engaging government forces, jihadists, and numerous opposition groups. Previous internationally mediated ceasefires have collapsed as militants continued attacks and government troops resumes their advance. Russia cited US failure to distinguish between moderate and extremist factions on the ground as the chief reason for the ceasefire collapse.
The Al-Qaeda affiliated al-Nusra Front is one of many internationally designated terrorist organizations operating in the Arab country.
