Intensified airstrikes by the U.S.-led coalition targeting the Islamic State are responsible for a “staggering loss of civilian life” in Raqqa, Syria, a United Nations investigator said Wednesday.

The northern Syrian city, the so-called capital of the Islamic State (ISIS), is where U.S.-backed forces, including Syrian Kurdish and Arab U.S.-backed rebel groups, last week began an offensive. That effort to retake the city from ISIS, also referred to as ISIL, was aided by U.S.-led coalition airstrikes.

But these increased strikes were in the crosshairs of Paulo Pinheiro, the chairman of the Independent International Commission of Inquiry for Syria, who gave the U.N. Human Rights Council his dire assessment of the situation for Syrian civilians, who “are in the unenviable role of being the target of most warring parties” and face “disastrous consequences.”

While Pinheiro told the U.N. body that a successful offensive “could liberate the city’s civilian population from the group’s oppressive clutches, including Yazidi women and girls, whom the group has kept sexually enslaved for almost three years as part of an ongoing and unaddressed genocide,” he underscored that the “imperative to fight terrorism must not […] be undertaken at the expense of civilians who unwillingly find themselves living in areas where ISIL is present.”

He said that the “that the intensification of airstrikes” as a result of the offensive “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.”

Those fleeing Raqqa, and countless others forced to join the ranks of internally displaced people across Syria, face “a wretched experience” and “are particularly vulnerable to violence,” Pinheiro said. He also pointed to “aerial bombardments by pro-Government forces” and other forced evacuations that leave civilians in peril.

According to Reuters,