A key United Nations official on Thursday called for a 48-hour cease-fire in war-torn Aleppo in order to let humanitarian groups bring food and medicine into the Syrian city, and Russia signaled that it's ready to support that idea.

UN envoy for Syria Staffan de Mistura said the cease-fire would be a "gesture of humanity from both sides" to help the two million people trapped in the divided city. De Mistura told reporters that he angrily left a meeting of the Humanitarian Task force after less than 10 minutes because not a single convoy had been allowed to reach and aide any of Aleppo's besieged areas.

Syria's civil war has raged for months despite a UN-backed cease-fire, in large part because the U.S. and Russia have been unable to come to terms over who the enemy is in that country. But in a sign of some progress, Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said Thursday his country is ready to support the UN special envoy's proposal as soon as next week.

"The Russian Defense Ministry is ready to support the proposal of the Special Envoy of the UN Secretary General for Syria Mr. [Staffan] de Mistura concerning the establishment of a 48-hour humanitarian pause to supply the population of the city with food and medical items and to restore life-support systems that were destroyed as a result of militia shelling," Konashenkov said. He added that the United States would need to provide guarantees that convoys will have safe passage.

The attention on Aleppo comes as a photo of a dusty and bloodied boy rescued from a destroyed building after an airstrike was shared widely on social media this week.

"We were passing them from one balcony to the other," Al Jazeera Mubashir journalist Mahmoud Raslan, who took the photo, told the Associated Press.

Omran Daqneesh, 5, is also seen in a video released by Aleppo Media Center, a pro-opposition activist group. According to the group, the video of Daqneesh was taken in the rebel-held Qateriji district of Aleppo late Wednesday. A reported Russian airstrike on the district killed at least three people and injured 12 others.

In the video, Daqneesh is seen being carried out of a damaged building and placed on a set in the back of an ambulance.

The boy was treated for head wounds on Wednesday night, a local doctor said. His parents and three siblings are believed to have survived the airstrike.

"The stunned, bloodied face of a child survivor sums up the horror of Aleppo," tweeted Adib Shishakly, a member of the opposition Syrian National Council.

According to the UN, more than 250,000 people have died in almost five years of war in Syria, with an additional 11 million people displaced by the conflict.