BEIRUT: US-led coalition raids on Raqqa in northern Syria have killed 29 civilians over the past 24 hours as American-backed forces battle the Islamic State (IS) group, a monitor said on Tuesday.
The Britain-based Syrian Observatory for Human Rights said nine women and 14 children had been killed in coalition air raids on Raqqa city since Monday evening.
It said 14 of the dead were members of one family. The toll could rise because of the number of critically wounded, it added.
The American-led coalition battling IS in Syria and Iraq on Tuesday entered its fourth year of operations. It began on August 8, 2014 in Iraq, moving later to battle the jihadists in neighbouring Syria .
The United States is backing an Arab-Kurdish alliance that is fighting to oust IS from Raqqa, its main Syrian stronghold, and the province of the same name. The Observatory, which relies on a network of sources inside Syria for its information, has regularly reported civilians killed by coalition strikes.
It says it determines what aircraft carried out raids according to their type, location, flight patterns and the munitions involved. The United States has admitted that its strikes caused the deaths of 624 civilians since 2014. Rights organisations say the number is far higher.
United Nations war crimes investigators in June expressed alarm at the rise in civilian deaths in the fight for Raqqa. Intensified air strikes had caused "staggering loss of civilian life" and led to 160,000 civilians fleeing their homes, Paulo Sergio Pinheiro, head of the UN Commission of Inquiry, told reporters.
Captured by the jihadists in 2014, Raqqa became a symbol of atrocities by IS in its self-declared "caliphate". The Syrian Democratic Forces alliance began a campaign to capture the city last year, slowly encircling the city before breaking into it for the first time in June.
They have since advanced in a pincer-like motion and taken around 45 percent of the city. The jihadist group has responded with a barrage of car bombs, suicide bombers, weaponised drones and snipers.
Progress inside Raqqa has been hampered by IS mines, which have slowed advancing SDF fighters and also had devastating consequences for civilians trying to flee.
To the southeast, Syrian government forces backed by their Russian allies are fighting IS in the oil-rich province of Deir Ezzor.
More than 330,000 people have been killed in Syria since the conflict began with anti-government protests in March 2011.