Air strikes by U.S.-led forces have killed 521 Islamist fighters and 32 civilians during a month-long campaign in Syria, a monitoring group which tracks the violence said on Thursday.
The Britain-based Syrian Observatory for Human Rights said the vast majority of the deaths, 464, were militants from Islamic State, an al Qaeda offshoot which has grabbed large areas of Syria and neighboring Iraq.
The attacks also killed 57 members of the al Qaeda-affiliated Nusra Front, the Observatory said. Six of the civilians were children and five were women, it added. […]