An intense wave of bombings unleashed on Aleppo by the Syrian government will be backed up by ground forces, a Syrian military source has said.

President Bashar al-Assad’s forces announced a new offensive on rebel held parts of the city late on Thursday, as peace talks between several world powers in New York failed to make any conclusive headway.

The unnamed source told state media on Friday that the attack will be a “comprehensive one” involving preparatory air strikes and boots on the ground that could go on “for some time.”

Aleppo, Syria’s largest city, has been the scene of some of the six-year-long conflict’s fiercest fighting. Regime bombing, assisted by Russian fighter jets since 2015, have levelled whole neighbourhoods and killed thousands.

The Syrian army and its allies have not launched a ground offensive on the city since 2012. The fresh round of intense strikes and reports of clashes on several edges of the city have sparked fears that a ground operation could be aimed at unseating rebels from Aleppo once and for all.

"Capturing Aleppo would be highly advantageous to Assad, solidifying his control of so-called 'useful Syria'. But it would have to be a monstrous campaign. An atrocity of this sort would resonate in history," a diplomat close to the International Syria Support Group process said.

Besieged residents said that they had never seen anything like the current renewed air campaign. Ammar al-Selmo, the head of the local civil defence rescue service, also known as the White Helmets, told Reuters, “What’s happening now is annihilation.”

Syrian girl rescued from rubble in Aleppo

A young girl was pulled alive from the rubble of a building on Friday – with volunteers using their bare hands to scrape away masonry and debris as five-year-old Rawan Alowsh cried intermittently, according to footage broadcast by Sky News. None of her family were thought to have survived the attack.

The UK-based Syrian Observatory for Human Rights (SOHR) estimated that 40 air strikes hit Aleppo overnight on Thursday, destroying the city’s main water pumping station.

Shelling continued throughout the day on Friday. The White Helmets, a volunteer workforce, said three of their four operation centres had been targeted, and two were now out of operation, as demand for their services increased.

At least 80 people died on Thursday, a member of the city’s forensic team told AP, but Friday’s bombing has been so intense that it has been impossible for monitors to safely document new injuries and casualties.

Approximately 250,000 people remain trapped in east Aleppo under siege conditions.

The situation in Aleppo on 23 September, with regime attacks and territory seen in red, rebels in green, Kurds in yellow and Isis in black (Liveuamap)

The Syrian army source said that all military operations would aim to avoid harming civilians and “allow them to flee from the terrorists.”

The army made attempts to advance in several districts but was repelled, said Zakaria Malahifji, a Turkey-based official for one of the main Aleppo factions. The Observatory said the army had made some progress in a southern district of the city.

The latest bombings showed that the aim of the Syrian government and its allies was to split the country, France's foreign minister has said.

“The bombings of the last few hours in Aleppo show the regime is playing the card of dividing Syria and its supporters are letting it happen,” Jean-Marc Ayrault said at the United Nations.

Elsewhere in Syria on Friday, the city of Homs, once one of the most active anti-regime cities in the country, finally conceded defeat.

Approximately 300 rebels and their families in the last rebel-held neighbourhood of Al-Waer were evacuated north, after accepting amnesty and surrendering to Assad’s forces.