Syrian National Coalition chief Anas al-Abdeh, in an interview with AFP, also praised a new-found unity among opposition factions that has seen the Fateh al-Sham Front -- which used to have ties with Al-Qaeda -- join forces with other rebels in the battle for Aleppo.
Over the weekend, opposition fighters succeeded in ending a three-week government siege of Aleppo's rebel-held east -- a major blow to the government forces of President Bashar al-Assad.
"I think it will pave the way for a proper political transition, something the international community is not taking sufficiently seriously."
Aleppo, once Syria's economic hub and one of the oldest cities in the Middle East, has been roughly divided between government forces in the west and rebel groups in the east since fighting there first broke out in 2012.
Also Read
Asked if the rebels could now take all of Aleppo in what would be the biggest blow to Assad of the entire war, Abdeh said: "I think it is just a matter of time. It will happen."
Abdeh said rebel forces had moved from a position of defence to attacking not just Syrian regime forces but their allies in Aleppo who he said included Iranian forces, Hezbollah and Iraqi militias.
"We are trying our best to push all these foreigners out of our land so our people live in peace and tranquility," said Abdeh.
He praised a new "political and military unity" among the rebels, saying this was "a key factor" behind the success of the opposition in Aleppo.