The Britain-based Syrian Observatory for Human Rights said on Thursday that the US-led campaign of airstrikes against "Islamic State" (IS) militants in Syria had killed 553 people since its launch a month ago.
The group, which has monitored the conflict in Syria since 2011, said the vast majority of those killed in the airstrikes were members of the jihadist group or other militants. It added that 32 civilians had also lost their lives.
It said the airstrikes in the provinces of Aleppo, Deir al-Zor, Idlib, Raqqa and al-Hassakah had killed 464 IS fighters and 57 militants from the al Qaeda-linked al-Nusra Front.
Of the civilians who died, six were children, the Observatory said.
A spokesman for US Central Command had said on Saturday that Washington took "reports of civilian casualties or damage to civilian facilities seriously" and would investigate each allegation.
The US has been carrying out airstrikes on IS militants in Syria since September with the aid of Arab allies. It is also leading a similar campaign across the border in Iraq, in which Britain and France are also taking part.
To justify its military intervention in Syria, Washington has cited Article 51 of the United Nations Charter, which enshrines the right of individuals or groups to defend themselves against armed attack.
The IS militants now control large parts of Syria and northern and western Iraq in their self-declared bid to establish an Islamic caliphate across the region. The jihadists have allegedly carried out widespread atrocities during their offensive, including enslaving women, killing and mistreating civilians and beheading Western hostages.
The IS militants add a complicating factor to the three-year civil war in Syria, which started off with protests against President Bashar al-Assad. Some analysts fear that the US intervention to combat the militants may enable al-Assad - whose rule Washington has declared "illegitimate" - to retain his hold on power.
tj, (Reuters, AFP)