Syrian rebels and troops fought fierce battles over a keenly contested neighbourhood of Homs on Tuesday, as fresh clashes broke out on the road linking Damascus to its international airport, a watchdog said. The fighting in Homs was focused on the Khaldiyeh district and comes one week into a massive army and pro-regime militia assault to reclaim rebel districts in the central Syria city, the Syrian Observatory for Human Rights said. Regime forces were backed by tanks, which pounded the neighbourhood, activists said. Fresh clashes also broke out Tuesday on the outskirts of Baba Amr, another strategic neighbourhood which had become a symbol of resistance to President Bashar al-Assad's regime before it was overrun by the army a year ago. "Rebels and troops are fighting on the edges of Baba Amr. The clashes are fiercest around Brazil street, and the army is intermittently bombing the district," said Observatory, which relies on a network of activists, doctors and lawyers for its reporting. Once an opposition bastion, the army seized Baba Amr from rebel hands last year after a relentless, month-long bombing campaign on the neighbourhood. Rebels two days ago launched a counter-offensive in a bid to retake Babr Amr, sparking heavy fighting during which the military launched artillery attacks and waves of air strikes.