Fierce clashes have been reported near Aleppo in northern Syria, as government forces try to surround rebels holed up in the strategic city, reports BBC.Monitoring group the Syrian Observatory for Human Rights said about 120 fighters on both sides had been killed around the town of Ratyan on Friday.As many as 20,000 refugees fleeing the fighting have spent the night at a border crossing with Turkey.Turkey says it is prepared to help the refugees but the frontier is shut.In the past few days, the Syrian army backed by Russian air power has made a series of gains in Aleppo province.Syrian state TV said on Friday that pro-government forces had seized Ratyan, just north of Aleppo city.