Aleppo laid bare: Shocking UN map shows areas of the city suffered '100 per cent destruction' - with more than 33,000 homes wiped out

• The heatmap was created using satellite imagery from throughout the war 
• Total damage of homes has increased over 150 per cent since May 2015
• Russia said on Thursday its air strikes in Syria have killed 35,000 rebel fighters
• Russia's Defence Minister said it halted a chain of revolutions in the Middle East

A shocking new map shows how more than 33,000 homes have been destroyed in Aleppo since the war began almost six years ago.

The map, which was created from satellite imagery obtained by the UN's Operational Satellite Applications Programme, also illustrates how total damage of residential buildings has increased over 150 per cent since May 2015.

The Russian intervention in Syria, involving heavy bombardment, began in September 2015 after an official request by from President Assad for military help.

The preliminary analysis, which has not yet been validated on the ground, was obtained using satellite imagery from the following dates: 18 September 2016, 01 May 2015, 26 April 2015, 23 May 2014, 23 September 2013, and 21 November 2010.

UNOSAT identified a total of 33,521 damaged structures within the extent of the map.

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The damaged homes are compared with the total numbers of buildings found in 2009 satellite image, captured before the war began.

More than 4,000 fighters left rebel-held areas of Aleppo, the Red Cross said Thursday, in the 'last stages' of an evacuation clearing the way for Syria's army to retake the city.

A week into the rebel withdrawal from the east of Syria's second city, the evacuation of fighters and civilians from the one-time opposition stronghold appeared to be reaching its final hours.

The loss of east Aleppo marks the biggest defeat for Syria's rebellion in more than five years of civil war and a major victory for President Bashar al-Assad, who on Thursday hailed his allies Moscow and Tehran.

'The liberation of Aleppo is not only a victory for Syria but also for those who really contribute to the fight against terrorism, notably Russia and Iran,' state news agency SANA quoted Assad as saying.

'It is also a defeat for countries hostile to the Syrian people who used terrorism to achieve their interests,' Assad said after a meeting in Damascus with Hossein Jaberi Ansari, an Iranian deputy foreign minister.

The evacuation effort has been hampered in recent days by heavy snowfall and freezing temperatures -- leaving evacuees waiting in unheated buses for hours -- but aid workers said it had resumed in earnest.

'Overnight between Wednesday and Thursday, in one of the last stages of the evacuation, more than 4,000 fighters were evacuated in private cars, vans, and pick-ups from eastern Aleppo,' said Ingy Sedky, the spokeswoman in Syria for the International Committee of the Red Cross.

She said about 34,000 people had left rebel areas of Aleppo under the evacuation plan, which the ICRC is assisting with.

'The bad weather, including heavy snow and wind, and the poor state of vehicles... mean things are moving much more slowly than expected,' Sedky said.

'The evacuation will continue for the entire day and night and most probably tomorrow (Friday). Thousands are still expected to be evacuated.'

It was unclear who exactly remained to be evacuated or how many were either fighters or civilians.

Russian air strikes in Syria have killed 35,000 rebel fighters and succeeded in halting a chain of revolutions in the Middle East, Defence Minister Sergei Shoigu claimed on Thursday.

Speaking at a gathering of top military officials that appeared designed to showcase Russia's military achievements, Shoigu said Moscow's intervention had prevented the collapse of the Syrian state.

'We are now stronger than any potential aggressor,' President Vladimir Putin said at the same event at the Defence Ministry in Moscow.

Shoigu said Russian aircraft had flown 18,800 sorties in Syria since the start of the Kremlin's operation there last year, destroying 725 training camps, 405 sites where weapons were being made and killing 35,000 fighters.

'The chain of 'colour revolutions' spreading across the Middle East and Africa has been broken,' Shoigu said.

Russia's intervention in Syria is widely seen as having saved President Bashar al-Assad's forces from defeat and as being crucial to their retaking full control of Aleppo.

Shoigu also said Russia's nuclear missile forces would next year be swelled by three extra units armed with modern weaponry and that the air force would receive five modernised strategic bombers.

But Putin warned that while Russia's military power had grown substantially, 'if we don't want that to change we had better not lose focus.'