US-backed fighters have launched a renewed attack on Islamic State group militants inside their Syrian bastion Raqa. Head of the Syrian Observatory for Human Rights Rami Abdel Rahman said that the Syrian Democratic Forces (SDF) started a counter-offensive on Friday night to retake Al-Senaa. <br/><br/>The SDF first ousted IS from Al-Senaa on June 12 but IS took back control again yesterday. Al-Senaa is key for both the Syrian Democratic Forces and IS because it is adjacent to the city centre. <br/><br/>The Observatory said today that 219 IS fighters and 193 civilians had been killed in Raqa since the US-backed SDF entered the city. <br/>