Syrian rebels said on Thursday they had started pushing into Hama, a major city where pro-government forces backed by intense Russian air strikes are trying to stave off a new rebel victory and halt the insurgents' lightning advance. Rebel commander Hassan Abdul Ghany posted on social media that the insurgents had begun to penetrate Hama. State media had earlier reported that pro-government forces had repelled an attack. Insurgents have been battling to try to enter Hama since Tuesday and there was heavy fighting overnight with the Syrian army and allied Iran-backed militia groups supported by a Russian bombardment, both sides said. The city lies more than a third of the way from Aleppo to Damascus and its capture would open the road to a rebel advance on Homs, the main central city that functions as a crossroads connecting Syria's most populous regions.