Dramatic video footage of children apparently fleeing sniper fire in east Aleppo has appeared on several US and UK news outlets.

The footage, recorded earlier this week by an activist and videographer in Aleppo, seems to show children flee from an evacuee ambulance under the sound of sniper fire, before taking shelter in a ruined building.

The BBC has not independently verified the footage.

You may find this video distressing.

The World Health Organization's Elizabeth Hoff, who is in Syria, has said negotiations are under way with the aim of re-starting evacuations, the Associated Press agency reports.

Ms Hoff said "there are a large number of women and children, and there are others, who are still inside and want to get out" - directly contradicting an earlier claim from Syria's allies in the Russian military.

Russia had claimed all the women and children have left the area.

It is not clear who is involved in the negotiations mentioned by Ms Hoff. Talks earlier this week broke down, with key parties saying they hadn't been consulted.

Rebels in east Aleppo told Reuters news agency that pro-government Iranian forces have detained about 25 cars full of civilians leaving the area.

They also said weaponry has been deployed on the road out. 

The head of the Fastaqim group told the agency his forces were preparing for conflict.

"Everyone is manning positions and the fronts. Readiness is at the highest level", he said.

With modern technology, the world has been able to follow some residents and activists in east Aleppo throughout the crisis.

Today there are unconfirmed reports that internet access in the area has been disrupted. However, a handful of accounts are still sending messages.

The battle for Aleppo is ending and the Syrian government now controls most of a city which had put up fierce resistance for years.

But the government's victory here doesn't mean the complicated war will end.

The BBC's diplomatic correspondent, Jonathan Marcus, says this is a major propaganda victory for President Bashar al-Assad's government - following an extraordinary turnaround that happened after Russia intervened to help defeat the rebels.

But the war will continue, he says, and will "lose none of its complexity".

Read more here.

Russian officials say Syrian government forces have retaken every district in Aleppo, and are in the process of clearing the last remaining pockets.

"The Syrian army's operation to liberate rebel-controlled eastern Aleppo neighbourhoods is complete," the defence ministry said in a statement.

Despite this, Reuters news agency reports that buses which had begun evacuation journeys out are now turning back towards the rebel-held areas.

It is not clear how much of the city the rebels still control.

Image source, AP

The UN estimates roughly 10,000 of the 50,000 people still living in rebel-held areas have been fighting against the government.

Elizabeth Hoff from the World Health Organization said this morning that there were "still large numbers of women and infants - children under five" among those waiting to leave.

Speaking from western, government-held Aleppo, she said: "They have been collecting themselves on the points where the buses and the ambulances were waiting for them.

"But now with the operation aborted they had to go back to their houses and this a great concern to us because we know that they are desperate to get out."

Image source, AP

Sources on the ground have been offering various explanations for the interruption.

• Government sources said rebels had blocked the evacuation of civilians from two pro-government towns elsewhere in Syria, agreed under the deal. 

• World Health Organisation official Elizabeth Hoff said the planned evacuation of the sick and wounded had been halted on Friday on orders from Russian forces, and that no reason had been given. 

• Syrian state media said the mission was suspended after rebels tried to smuggle heavy weapons and captives out with them as they left the besieged enclaves. 

• Both sides have accused each other of firing on the buses.

Image source, AFP

We'll be posting live updates on the suspended Aleppo evacuations - if you want more, you can read the full story here in one go.

Welcome to Friday's coverage on the Aleppo evacuations.

This story has dominated world news coverage this week, as efforts to remove people from the shrinking rebel-held areas in the east of the city have hit repeated obstacles.

A deadlock seemed to have been broken on Thursday, when strings of buses carried thousands of people out. 

But now the Syrian government has suspended the evacuation, saying rebels breached the terms of an agreed ceasefire. A condition of the agreement was that civilians were to be moved out of pro-government, rebel-surrounded towns at the same time. But sources in the Syrian government say rebels blocked that evacuation - so the one in Aleppo is off for now.

The UN says there are 50,000 people still in districts of eastern Aleppo that are held by the rebels. Those areas have been under siege for months, and Syrian forces have advanced on them over the past week, bringing most of the city under government control.

We're pausing our live coverage of the situation in Aleppo for now. The latest updates and on overview of the situation can be found in our main story.

A second convoy of evacuees left Aleppo late on Thursday, Syrian state television reported.

The convoy consisted of 15 buses, and would continue in "batches", the report said.

The buses are heading towards rebel territory in western Aleppo province.

Russian news agency Interfax also confirmed the report.

"Just like the previous convoy, it is carrying militants and their family members along a special route ... where they will change onto another form of transport and proceed to Idlib," it said, quoting the Russian Centre for Reconciliation of Opposing Sides in Syria.

The UN Children's Fund (Uncief) is urging all parties to the conflict to allow the immediate evacuation of children from rebel-held Aleppo.

Image source, AFP

The UK's foreign secretary summoned the Russian and Iranian ambassadors in London over the situation in Syria earlier on Thursday.

Boris Johnson accused both countries of failing in their obligations under international humanitarian law.

"They deserve no credit for the fact that an evacuation appears to be under way," he said in a statement.

"Having inflicted such suffering on the people of eastern Aleppo, Iran and Russia cannot expect praise for allowing some people to escape at the final hour."

Iran and Russia support Syria's government, while the UK backs the opposition.

The pro-opposition Aleppo Media Centre has published some striking video footage of the evacuations, which was shot using a drone.

A senior official from the International Committee of the Red Cross has said it expects to evacuate 2,000 people from rebel-held Aleppo on Thursday - double the number estimated to have left in the first convoy. 

The ICRC's Middle East regional director, Robert Mardini, told the Reuters news agency that many more rotations of buses and ambulances would be needed over the next few days.

He said the morning's activity was "the first step - it was a positive one".

UN humanitarian adviser Jan Egeland has expressed concern that the "window" for evacuations may be narrow.

Referencing a video of orphans in Aleppo asking to be rescued, he tweeted: "UN now working with parties on the ground to get these children out of the Aleppo crossfire. The window we have now we may never get again."  

Image source, Getty Images

In Syrian President Bashar al-Assad's earlier statement, he claimed the "liberation" of Aleppo would be a turning point in world history.

"People do not remember time they remember history ... we say before Christ, and after Christ. We say before revelation on prophet Muhammad, and after the revelation. 

"History is not the same before and after,"  he said.

"I think after liberating Aleppo, we will say not only the Syrian situation, but also the regional and international situation is different - before liberating Aleppo and after it."

Mr Assad paid tribute to the citizens of Aleppo for their resistance and to the Syrian army, the country's new history, he said, started being written by its citizens six years ago.

Aleppo, once Syria’s largest metropolis, will soon join Grozny, Dresden and Guernica by making history for being destroyed a commentary in The Economist says., external

Even if many who remain in the last Sunni Arab enclave receive the safe passage they have been promised, "their four-year ordeal has blown apart the principle that innocent people should be spared the worst ravages of war".

"Aleppo’s fall is proof that Mr Assad has prevailed and of Iran’s influence. But the real victory belongs to Russia, which once again counts in the Middle East." 

The West "has done no more than rehearse diplomatic phrases" when confronted by Mr Assad’s atrocities, the newspaper says.

"By failing to stand up for what it is supposed to believe in, it has shown that its values are just words - and that they can be ignored with impunity."