Heavily armored Syrian government forces have begun a ground attack on the rebel-held eastern part of Aleppo city, spearheaded by elite army unit according to a pro-Syrian government militia commander who spoke to Reuters.
The initiation of a ground offensive follows on from days of aerial bombardment which has killed hundreds in the besieged city in northern Syria, effectively ending a fragile ceasefire which was negotiated by Russia and the US on September 9.
A senior rebel official told Reuters the ground attack is the biggest since the Russian-backed offensive began last week and took place at four rebel positions simultaneously.
As Syrian president Bashar al-Assad seeks to regain control of Aleppo, on Tuesday Syrian army and its allies targeted a key southern gateway into the city. According to Reuters, the army "fought intense clashes with insurgents in the opposition-held 1070 Apartments district of southwestern Aleppo on Tuesday, senior combatant sources on both sides said."
Capturing this area would allow the government to ease its own access into the city while consolidating a siege on rebel-held districts.
Reports earlier this week suggested a major ground force of up to 3,000 Iranian-backed fighters was converging on Aleppo in preparation for this assault.
Some 250,000 people are believed to be trapped in the eastern part of the city and while the UN revealed it had been able to deliver aid to 60,000 people trapped in four cities in Syria for the first time since April, huge concerns remains for those in Aleppo which it cannot reach.
"We are extremely concerned about the more than 250,000 people trapped in eastern Aleppo city who are cut off from food, water, medicine, and other essential supplies," Jakob Kern, Syria country director at the UN's World Food Programme said.
"We call on all parties to this terrible conflict to immediately open transport routes that allow unconditional, unimpeded, sustained and safe humanitarian access to those in eastern Aleppo and every family across Syria that needs our support," he added.
The Syrian Observatory for Human Rights, an independent monitoring group that relies on local accounts to document airstrikes and military operations within Syria and Iraq, said on Tuesday that deaths in the last 24 hours have totalled 26, including six children, following attacks targeting the eastern neighbourhoods of Aleppo.
Aleppo has been bombarded with airstrikes since for almost a week now, with hundreds of people being killed including dozens of children. While there have been multiple reports of phosphorous bombs being used in the attacks, there is also reports that the Russian warplanes take part in the airstrikes are dropping so-called "bunker-busting bombs".
Describing the impact of these bombs, Yassin Mohammed, a 51-year-old taxi driver from East Aleppo told Middle East Eye they felt like "an earthquake."
"It didn't just last a few seconds, but was followed by a strong shake and the sounds of rocks falling everywhere. The sound was terrible, it was as if the ground was shaking or there was an earthquake."
"The Russian and the Israelis and even the Americans allowed the (Assad) regime to seemingly exterminate eastern Aleppo and experimenting with new weapons on us, Mohammed said. "We have become a weapons testing site and the whole world is watching in silence. No one is doing anything to stop these criminals."
On Sunday, during an emergency meeting of the UN Security Council, the UK ambassador to the UN, Matthew Rycroft, referred to this type of device. "Bunker-busting bombs, more suited to destroying military installations, are now destroying homes, decimating bomb shelters, crippling, maiming, killing dozens, if not hundreds."