US-led coalition strikes on Sunday killed 27 civilians in part of Raqqa city, Syria, held by the so-called Islamic State group, according to the Syrian Observatory for Human Rights monitor.

Seven children were among the dead in the strikes that "hit the densely-populated Al-Badu area in the centre of the city," Observatory director Rami Abdel Rahman said on Monday.

According to the Observatory, at least 125 civilians have been killed in a week of US-led strikes on Raqqa city, including those who died on Sunday.

"There are civilians killed each day in coalition strikes... The closer the fighting gets to the densely-populated city centre, the more civilian deaths there are," Abdel Rahman said.

Once a jihadist stronghold, the Syrian Democratic Front has captured over half of Raqqa city after entering the city in June.
The SDF is heavily backed by the US-led coalition, which regularly launches airstrikes against the jihadists, reportedly killing scored of civilians.

However, people who have escaped say there are far fewer than the U.N. estimate of 20,000 people left, Reuters reported.