The UN is reporting that the coalition airstrikes led by the US is causing a “staggering” number of civilian deaths in the Syrian city of Raqqa. The city was taken by Islamist State forces in 2014 and has been cited by the IS as their “capital” and their “caliphate”.

US-backed SDF (Syrian Democratic Forces) are attempting to wrest control of the city from the IS forces trapped inside in heavy fighting.

Paulo Sérgio Pinheiro, chairman of the U.N. Independent International Commission of Inquiry on Syria, said Wednesday that coalition airstrikes have deepened the suffering in the city held by extremist fighters.

“We note in particular that the intensification of airstrikes, which have paved the ground for an SDF advance in Raqqa, has resulted not only in staggering loss of civilian life, but has also led to 160,000 civilians fleeing their homes and becoming internally displaced,” Pinheiro told the U.N. Human Rights Council in Geneva. He referred to the Syrian Democratic Forces (SDF), a U.S.-backed militia dominated by Syrian Kurds.