U.N. investigators say Syrian government forces and opposition fighters are targeting civilians in a way that has led to "unspeakable suffering."

The report by the Independent International Commission of Inquiry on Syria says with "each passing day there are fewer safe places in Syria."

The report released Tuesday says government forces have consistently failed to employ precision weapons "when attacking targets in dense urban areas, causing mass civilian casualties."

It said the government use of barrel bombs in aerial attacks against whole areas rather than specific targets "is in violation of international humanitarian law and, as previously documented, amounts to the war crime of targeting civilians."

It added that indiscriminate attacks on civilian-inhabited areas are committed across Syria "by most, if not all, of the warring parties."