The U.S.-led coalition fighting ISIS in Syria has stepped up its attacks on the militant Islamist group 's de facto capital , with 30 airstrikes targeting Raqqa overnight , the London-based Syrian Observatory for Human Rights said Sunday . Separately , another opposition activist group based in Raqqa reported that about 30 airstrikes by `` the crusader alliance '' targeted areas northwest of the city . Previously , coalition strikes have primarily targeted Kobani , near the Turkey border . The attacks in Raqqa mark an increase in coalition activity there . Last week , almost 100 people were killed in Syrian government airstrikes in Raqqa , the observatory said . Many more were critically injured . Government warplanes carried out at least 10 airstrikes in Raqqa , targeting the city 's al-Hani Mosque and the public souk , or market , the observatory said , using reports from activists and residents on the ground . Extremists have made the city , which sits on the banks of the Euphrates River , the de facto capital of their self-declared Islamic State that stretches across large areas of Syria and Iraq . The city is known as a place where ISIS puts training centers , weapons depots and accommodations for fighters . During the Syrian conflict , the group has also seized military bases from the Syrian regime near the city and in the wider Raqqa province . Syria has been embroiled in a three-year civil war , with government troops battling ISIS and other rebels . Fighting raged across the country on Sunday , the observatory said , with more than 40 people reported dead in airstrikes , shelling and raids . A leader of al Qaeda affiliate Jabhat al-Nusra was among those killed in clashes north of Aleppo , the observatory said . The Islamist militant group , also known as al-Nusra Front , is also trying to establish an Islamic state , though primarily in Syria . It has been gaining ground and has emerged as one of the most effective groups fighting the Syrian regime during the civil war , drawing on foreign fighters with combat experience in Iraq and elsewhere . At least 40 fighters killed in Syrian city of Kobani .
More than 100 were killed in clashes across Syria , observers say . At least 30 rockets hit Damascus overnight , according to opposition activist groups . Attacks mark increases in activity in Damascus , which ISIS had made its de facto capital .