HAMILTON, Canada

UN Secretary-General Antonio Guterres called for urgent action Thursday to ensure accountability and an inclusive political transition in Syria, as the country's civil war marks 14 years since its outbreak.

"This month marks 14 years since the Syrian people stood up in peaceful protest for their universal rights and freedoms, only to be met with brutal repression," Guterres said in a statement.

He said that the "unimaginable" human cost of the war that “began as a call for peaceful change, turned into one of the world’s most devastating conflicts, with an incalculable human cost.”

"Hundreds of thousands were killed, disappeared, tortured, and died horrific deaths. The war saw the use of chemical weapons and, barrel bombs indiscriminately killing men, women and children," Guterres noted.

The UN chief highlighted the destruction of vital infrastructure.

"The carpet bombing of hospitals, schools, and homes erased any semblance of normal life," he said. "Yet, the Syrian people never wavered in their steadfast and courageous calls for freedom, dignity and a just future.”

Citing recent developments in Syria since Dec. 8, Guterres said that "there is renewed hope that Syrians can chart a different course and the chance to rebuild, reconcile, and create a nation where all can live peacefully and in dignity."

He warned that the opportunity for a brighter future remains fragile, and urged for an end to the escalation of violence.

"All violence must stop, and there must be a credible, independent, impartial investigation of violations and those responsible must be held accountable," he said.

Guterres urged Syria's interim government to act on their commitments for an inclusive and credible transition.

"Now is the time for action. Bold and decisive measures are urgently needed to ensure that every Syrian -- regardless of ethnicity, religion, political affiliation, or gender -- can live in safety, dignity and without fear."

Reaffirming the UN's readiness to assist in Syria's recovery, Guterres said: "We stand with the Syrian people towards the promise of a better Syria -- for all Syrians."

"Together, we must ensure that Syria emerges from the shadows of war into a future defined by dignity and the rule of law, where all voices are heard, and no community is left behind," he noted.

Bashar al-Assad, Syria's leader for nearly 25 years, fled to Russia after anti-regime groups took control of Damascus on Dec. 8, ending the Baath Party's regime, which had been in power since 1963.

Ahmed al-Sharaa, who led anti-regime forces to oust Assad, was declared president for a transitional period in late January.