It shows Assad regime helicopters dropping barrel bombs on children below. Those that are still alive are weeping and in pain but the ones who are already dead look serene and at peace.

"Somehow he thought that the children who died are in a better place than those who are alive,"Dr Sahloul said."This is what happens to children in Aleppo and in other places."

The battle for Aleppo,divided between rebels in the east and government forces in the west,has become one of the most important and destructive of Syria's five-year war. It was not immediately clear whether Ali's death had been counted in the 168 civilians that the observatory said had been killed by Russian or regime airstrikes. Another 165 - among them 49 children - have also died after opposition shelling on the city's government-held western districts.

"Empathy and outrage must be matched by action,"said UNICEF executive director Anthony Lake in a statement late on Friday."Children of Omran's age in Syria have known nothing but the horror of this war waged by adults. We all should demand that those same adults bring an end to the nightmare."

Such calls are likely to fall on deaf ears. The Syrian conflict has turned into a knotty patchwork of proxy wars,none of which are close to resolution. While the Assad regime is now propped up by the funding and military might of Iran and Russia,rebel opposition groups of varying ideologies are supported by the United States,Turkey and Persian Gulf monarchies.

Russia said on Thursday it would stop attacks on Aleppo for 48 hours next week to allow delivery of humanitarian aid,indicating it would also prevent Assad's forces from bombing there,provided the United States could guarantee a similar pause by the"so-called moderate opposition."

As it stands,that promise is unlikely to come to fruition. Activists said Saturday that another four children,two women and a man were killed in the rebel-held Old City overnight,after an airstrike destroyed their home.

Photographs appeared to show the sole survivor of the attack,Ali Abul Jood,heaving breeze blocks from the rubble of his home in search of the children underneath.

"We tell our children now that we're sorry,"said a local English teacher,Abdulkafi al-Hamdo."They're not American,they're not French. When they die,you won't see them on the news."

Washington Post,Telegraph,London