REINFORCED Syrian troops advanced, yard by yard, against Islamist insurgents for control of Aleppo yesterday under crushing Russian air support.

Soldiers and volunteer militia struck out from the Ramouseh cement factory in the city’s south-west — liberated on Monday — towards the nearby gas plant and the main highway five.

A huge blaze raged at the cement factory after fighters of the newly rebranded Levant Conquest Front — formerly the al-Qaida affiliated Nusra Front — targeted fuel tankers there.

Russian and Syrian jets pounded the complex of military colleges two miles to the west through which the militants are trying to move thousands of men for an assault on government-held west Aleppo. Russian short-range ballistic missiles and rocket artillery also rained down on the site.

The Syrian army has reportedly sent 100 more tanks and 400 armoured personnel carriers to Aleppo in a bid to close the recent breach in their encirclement of 5,000 jihadists in the ruined east of the city.

On the north side of the gap, jets also struck the half-built 1070 housing project in the al-Hamdaniya area.

On Monday Russia’s deputy United Nations envoy Vladimir Safronkov warned the security council against attempts to exploit the humanitarian situation in Syria for political gain.

He said the “terrorists” in Aleppo were using civilians as human shields, shelling humanitarian corridors set up by the government and stealing aid supplies.

Islamic State has taken advantage of the situation in the north to launch a surprise offensive in southern Suweida province, after failing to take the al-Walid border crossing from the Iraqi army.