Published on 12:00 AM, December 11, 2016

World talks on as Aleppo bleeds

Smoke rises from a rebel-held area of Aleppo, Syria. Photo: Reuters

Air strikes pummelled the shrinking rebel enclave in Aleppo yesterday as US Secretary of State John Kerry said the Syrian regime's "indiscriminate bombing" amounted to crimes against humanity.

Western powers meeting in Paris called for the resumption of peace talks and for civilians to be allowed to leave Aleppo, where tens of thousands have already fled a fierce regime offensive.

The diplomatic flurry came as a US-backed alliance announced it would launch the second phase of its battle for the Islamic State group's de facto Syrian capital Raqa further east.

"The indiscriminate bombing by the regime violates rules of law, or in many cases, crimes against humanity, and war crimes," Kerry said after the talks in Paris, urging Russia to do its "utmost to bring it to a close".

US and Russian officials meanwhile were to gather in Geneva for what Kerry described as a bid to stop the city from "being absolutely, completely, destroyed".

In less than a month, forces loyal to President Bashar al-Assad have overrun around 85 percent of east Aleppo, a rebel stronghold since 2012.

The UN's Syria envoy Staffan de Mistura said the world is watching "the last steps" in the Aleppo battle and evacuating civilians must be a priority.

Both Moscow and Damascus have rejected talk of a ceasefire without a rebel withdrawal from the city -- a demand that opposition groups have refused.

Air strikes and regime rocket fire battered the last remaining rebel districts yesterday, according to the Syrian Observatory for Human Rights.

"The bombing is unreal," said Ibrahim Abu al-Leith, spokesman for the White Helmets rescue force inside Aleppo.

"The streets are full of people under the rubble. They are dying because we can't get them out," he added.

A man on a wheelchair flees with others after an air strike. Pictures were taken on Friday. Photo: Reuters

Since November 15, rebel fire on regime-held west Aleppo killed 129 people, including 39 children. Another 413 civilians, among them 45 children, have been killed in east Aleppo in the same period.

The fall of east Aleppo would be the biggest blow for the rebels since Syria's conflict broke out in 2011.

Meanwhile, the army said it has sent reinforcements to Palmyra, where Islamic State fighters have advanced to its outskirts in some of the heaviest fighting since the group lost the historic city earlier this year.

A rebel commander said the IS attack was forcing the Syrian government to divert troops from Aleppo. The renewed assault, which began late on Thursday, has killed dozens of Syrian soldiers and quickly taken over grain silos and control of some oil and gas fields around Palmyra, sources said.

A US-led coalition which is separately fighting against the jihadist militants said late on Friday it had destroyed 168 IS oil tanker trucks near Palmyra in a large air raid.