In just a few days, a patchwork of forces has seized control of a broad stretch of land in the west and northwest of Syria.
A Syrian opposition leader in exile appeared intent on Monday on capitalizing on rebels’ recent startling gains in the country, demanding on Monday that President Bashar al-Assad commit to a political transition.
The opposition leader, Hadi al-Bahra, spoke from Turkey as rebels continued their advance through Aleppo, once Syria’s largest city, and the surrounding areas.
In just a few days, the patchwork of forces has seized control of a broad stretch of land in the west and northwest of the country, according to the rebels and the Syrian Observatory for Human Rights, a British-based war monitor.
While Mr. Al-Bahra does not speak for the rebels, their capture of Aleppo has seemingly reinvigorated his group’s longstanding demands for a democratic transition.
Mr. Al-Bahra heads a group of political and military organizations known as the National Coalition for Syrian Revolutionary and Opposition Forces that oppose Mr. Al-Assad. The group claims to represent a majority of opposition parties, but it has become increasingly irrelevant as the Syrian civil war has dragged into its second decade.
He told a news conference broadcast from his base in Istanbul that the rebel offensive was supported by a population weary of crimes committed by Mr. al-Assad along with his Iranian and Russian backers.
The fighting will continue, he said, until the Syrian leader acquiesces — a prospect that Mr. Al-Bahra said the opposition was prepared for.
Negotiations could start “tomorrow,” he added.
Mr. Al-Bahra demanded the implementation of the stalled 2015 United Nations Security Council resolution 2254, which lays out a road map for Syria’s political transition, starting with a cease-fire. It is, he said, “the only sustainable political solution in Syria.”
“We have the right to use whatever means to ensure its implementation,” he said.
Jacob Roubai contributed reporting.