U.S.-led air strikes have killed around 521 terrorist fighters and 32 civilians during a month-long campaign in Syria

U.S.-led air strikes have killed around 521 terrorist fighters and 32 civilians during a month-long campaign in Syria, a monitoring group said on Thursday.

The Britain-based Syrian Observatory for Human Rights said the vast majority of the deaths, 464, were militants from the so-called “Islamic State” terrorist group, 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.