Fierce fighting between Syrian government forces and the Islamic State group has killed 64 combatants in Raqa province over a 24-hour period. The clashes come with the army pressing an advance through Raqa, in northern Syria, towards neighbouring Deir Ezzor, the only remaining province of the war-ravaged country still in the hands of IS militants. <br/><br/>The Syrian Observatory for Human Rights, a Britain-based monitor, said the fighting had claimed the lives of 38 militants and 26 pro-regime combatants since yesterday morning. It takes to 145 the overall death toll in six days of fighting in villages on the banks of the Euphrates River in the east of Raqa province, near Deir Ezzor. <br/><br/>IS said in a statement yesterday that its members had killed dozens of regime combatants in intense fighting lasting hours. Observatory director Rami Abdel Rahman told AFP that the regime is fighting to secure a foothold in Raqa province in order to advance in Deir Ezzor.