US Secretary of State John Kerry
John Kerry denounced the war in Aleppo between the Syrian regime and opposition rebels.Reuters

United States Secretary of State John Kerry on Thursday accused President Bashar al-Assad-led Syrian government of carrying out a "massacre" in Aleppo even as thousands were being evacuated from the war-ravaged city.

Syrian rebels had prepared to withdraw from Aleppo on Wednesday after a ceasefire agreement was struck, ending five years of violence in the Syrian city. The truce deal was struck after talks between Russia, President Assad's main ally in the war against rebels, and Turkey, a leading supporter of the rebels. However, the evacuation deal collapsed within hours after reports emerged of pro-Damascus Shi'ite militias obstructing evacuation of people in the region, and a new one was put in place.

Kerry defended the US diplomatic efforts to bring an end to the war backed by Russia, Iran and Shi'ite militias. As Washington continued to press for ceasefires, it had to sit back on the sidelines and watch the situation aggravate.

"There is absolutely no justification whatsoever for the indiscriminate and savage brutality against civilians shown by the regime and by its Russian and Iranian allies over the past few weeks, or indeed for the past five years. We are seeing the unleashing of a sectarian passion," Kerry said in a news briefing in Washington.

"The Assad regime is actually carrying out nothing short of a massacre," he added, citing the number of deaths and hostilities in Aleppo.

Around 50,000 people trapped
The United Nations peace envoy for Syria, Staffan de Mistura, and French Foreign Minister Jean-Marc Ayrault on Thursday said that around 50,000 civilians were still trapped in eastern Aleppo even as the evacuation deal was underway.

"There are 50,000 people, including 40,000 civilians unfortunate enough to live in that part of the city. The rest are fighters, numbering between 1,500 and 5,000, and their families," de Mistura told reporters in Paris. "Our priority is for our UN colleagues to be present with the people (who have been evacuated) and that the fighters be respected under the terms of this deal." 

The war between the Opposition rebels and the Assad-backed Syrian regime came to an end after the Syrian coalition captured almost all remaining besieged areas from rebels in eastern Aleppo. The evacuation deal marks the biggest victory for Bashar-al Assad's regime in the country yet.

According to Syrian state TV reports, around 4,000 rebels and their families would be evacuated from eastern districts on Thursday.