A shocked Syrian boy pictured sitting in an ambulance covered in blood and dust after an airstrike became a symbol of civilian suffering in Aleppo Thursday, drawing worldwide attention.
As international concern mounted, President Bashar al-Assad's key ally Russia said it was ready to halt fire in the battleground northern city for 48-hour "humanitarian pauses" from next week.
The announcement followed pleas from the United Nations and the European Union for a halt in the fighting in divided Aleppo to allow aid deliveries.
The haunting image of four-year-old Omran sitting dazed and bloodied in an ambulance reverberated around the globe, much like the photo of three-year-old Aylan Kurdi whose body washed ashore on a Turkish beach last year.
Omran was pulled from the rubble after an air raid on Wednesday in the rebel-held district of Qaterji in the southeast of Aleppo, which has been devastated by the five-year war.
"I've taken a lot of pictures of children killed or wounded in the strikes that rain down daily," said photographer Mahmoud Rslan who captured the image.
"Usually, they are either unconscious or crying. But Omran was there, speechless, staring blankly as if he did not quite understand what had happened to him," he told AFP by telephone.
Opposition-held neighbourhoods in the city are frequently targeted by air strikes including barrel bombs dropped by regime helicopters.
Syrian and Russian aircraft have been carrying out intense air strikes this week on opposition strongholds across northern Syria to prevent rebels sending reinforcements to Aleppo, a monitoring group said.
Air strikes on Idlib city, 60 kilometres (35 miles) southwest of Aleppo, killed 25 people including 15 civilians on Wednesday, according to the Britain-based Syrian Observatory for Human Rights.
Regime aircraft continued to pound rebel positions across Idlib province on Thursday as well as parts of Aleppo province, it said.
"Regime and Russian aircraft are carrying out dozens of raids every day on Idlib province and the west of Aleppo province to prevent reinforcements reaching rebel positions," said Observatory head Rami Abdel Rahman.
Aleppo has been the scene of intense fighting since July 31, when the "Army of Conquest" alliance of rebels and jihadists launched a major offensive to break a regime siege of opposition-controlled districts.
But neither side has achieved a decisive victory despite hundreds dead on both sides.
Despite its air power, the regime has been unable to gain headway in street-to-street battles, said Abdel Rahman.
"The rebels have put all their forces into this battle and regime forces have been exhausted," he said.
On Thursday, the regime continued to pound the rebel-held east of Aleppo where 146 civilians including 22 children have died in air strikes since 31 July.
In Geneva, UN envoy Staffan de Mistura cut short the weekly meeting of the humanitarian taskforce headed by the United States and Russia, in protest at the failure of warring parties to allow aid to reach civilians.
"Not one single convoy in one month has reached any of the humanitarian besieged areas," he told reporters.
Russian defence ministry spokesman Igor Konashenkov later announced that Moscow was "ready to implement the first 48-hour 'humanitarian pause' to deliver humanitarian aid to Aleppo residents" next week.
The Syrian conflict has killed more than 290,000 people and displaced millions since it began in 2011 with the brutal repression of anti-government demonstrations.
More than 17,700 people are estimated to have died in custody in Syria since then, an average of more than 300 each month, Amnesty International said Thursday.
Syrian authorities were committing torture on a "massive scale" in government prisons including beatings, electric shocks, rape and psychological abuse that amount to crimes against humanity, the watchdog said.
Syria's war now involves a range of combatants including Western- and Gulf-backed rebels, jihadists, Kurds and pro-regime forces supported by Russia and Iran.
On Thursday regime aircraft bombed Kurdish positions for the first time since the conflict erupted, hitting several checkpoints and bases in the northeastern city of Hasakeh, the Observatory said.
The raids followed heavy clashes a day earlier between Kurdish fighters and pro-government militia that left 11 people dead.
The two sides share a common enemy in the Islamic State jihadist group but there have been tensions between them in Hasakeh.
Washington regards the Kurds as the most effective fighting force on the ground in Syria and has provided weapons and special forces military advisers.