GENEVA (Reuters) – States backing Syria’s peace process must stop the warring parties from attacking unlawful targets such as hospitals and other civilian sites, U.N. war crimes investigators said in a statement on Wednesday.

Air strikes, shelling and rocket fire had been consistently used in recent attacks on civilian areas, the U.N. Commission of Inquiry on Syria said in a statement.

“Failure to respect the laws of war must have consequences for the perpetrators,” its chairman, Paulo Pinheiro, said.

“Until the culture of impunity is uprooted, civilians will continue to be targeted, victimized and brutally killed.”

International law requires all parties to the conflict to distinguish between lawful and unlawful targets, but that distinction had been ignored and some recent attacks had been war crimes, the statement said.

It cited an attack on the al-Quds hospital in Aleppo governorate on April 27 and other attacks on nearby medical facilities, and air strikes on markets, bakeries and a water station, as well as the May 5 attack on a refugee camp in Idlib.

Those attacks all happened after a two-month ceasefire, brokered by Russia and the United states, unraveled, and Syrian government forces said they would launch an assault to recapture rebel-held areas of Aleppo.

The statement did not explicitly attribute blame for attacks on civilians, but only Syria’s government and its ally Russia are using aircraft in the conflict.

U.N. High Commissioner for Human Rights, Zeid Ra’ad al-Hussein, said last week that initial reports suggested Syrian government aircraft were responsible for the attack on the refugee camp in Idlib governorate, which killed about 30 people. Syria’s military said they had not targeted the camp.

(Reporting by Tom Miles; Editing by Louise Ireland)