On nighttime of September 20, members of the terrorist organization Al-Nusra Front launched a major offensive against the Syrian army in the area southwest of Aleppo, as confirmed by the Russian defense ministry. Militants used mortars and rockets to fire at the building of the Military Academy "where [there are] cameras to observe a truce in the southwest of Aleppo," the statement said.

Aleppo, once Syria's commercial and industrial hub, has been divided roughly in two since 2012, with the government controlling the west while leaving the rest to the rebels.

The Russian center in Syria confirmed that the Al-Nusra Front occupied the neighborhood Al Shuqayyif and the one-mile Castello Road. These rebel-held areas saw the heaviest air strikes in months overnight, as a week-old truce collapsed.

An AFP news agency journalist reported that his entire street in the Bustan al-Qasr district was left burning after warplanes dropped incendiary bombs.

13 people, including three women and three children, are believed to have died, according to Rami Abdul Rahman, the UK-based monitoring group's director.

The Aleppo Media Centre said the fires were caused by "incendiary phosphorus bombs". Video footage posted by it and another pro-opposition activist group, Thiqa, showed intense blazes lighting up the night sky.

Fighting also erupted in the southern district, where rebels are attempting to break a siege by government forces. They have suffered heavy losses in manpower and equipment in Aleppo attempts at conquest Card 1070, these roads Castillo.

Two million people are caught up in the battle for the city, and delivering aid to them had been a key part of the cessation of hostilities agreement brokered by the Russia and United States. However, no deliveries have taken place so far.

A deadly attack on an aid convoy and Syrian Arab Red Crescent warehouse outside Aleppo on Monday, for which Moscow and Washington have blamed each other, prompted the UN to temporarily suspend deliveries across Syria.

But following the pause, a convoy on Thursday entered Muadhamiya, a suburb of the capital, Damascus, where some 40,000 people are living under siege, the UN tweeted.

A spokesman hopes the UN will reach Aleppo "in the near future."