US-led raids on Raqqa killed 59 civilians in three days: monitor

The Syrian Observatory for Human Rights said 21 children were among at least 59 civilians killed in the air strikes since Monday, after more corpses were dug out from under piles of rubble.

With air support from the multinational coalition, a Kurdish-Arab alliance on Thursday battled the militants in Raqqa's Old City, of which it now controls 70 percent, the Britain-based group said.

The Syrian Democratic Forces also fought IS in the western district of Al-Daraya and the northwestern neighborhood of Al-Barid, as well as on the outskirts of the central district of Al-Murur, it said.

The coalition has repeatedly stressed it takes every precaution to avoid civilian casualties.

But it has recognised 624 such deaths in its air strikes since 2014, a figure which many rights groups say is vastly underestimated.

According to the United Nations, 25,000 civilians are trapped inside Raqqa, the extremist group's de facto Syrian capital.

The SDF launched an operation to capture Raqqa province from IS last year, and in June the alliance broke into Raqqa city for the first time.

It now holds more than half of the city, but the fighting has proved fierce and civilians have been killed both in the crossfire and while trying to flee.