BEIRUT - Attacks by the US-led coalition against Islamic State in the Syrian city of Raqqa last year may have broken international law by endangering the lives of civilians, rights group Amnesty International said on Tuesday.During its campaign to recapture the group's Syrian capital, the coalition did not take enough account of civilians or take the precautions necessary to minimize harm to them, Amnesty said in a report.It documented the cases of four families whose experiences it said were emblematic of wider patterns and provided "prima facie evidence that several coalition attacks which killed and injured civilians violated international humanitarian law."The coalition has responded to previous accusations that it caused civilian casualties by saying it was careful to avoid them and investigated all reports that they had occurred.The campaign to capture Raqqa was waged from June to October last year by the Syrian Democratic Forces (SDF), an alliance of Kurdish and Arab militias backed by coalition warplanes and special forces troops.Reuters reporters in Raqqa during and after the campaign said that air strikes and fighting had caused massive destruction throughout the city, laying waste to entire districts.The jihadist Islamic State had once used the city as the administrative center of its self-declared caliphate, making it a planning center for attacks by its followers around the world. During the battle for Raqqa, IS fighters made it harder for the coalition offensive to avoid civilian deaths by operating among them and using them as human shields, Amnesty said.Amnesty said it had interviewed 112 civilian residents of Raqqa during field research there in February, visiting the sites of 42 air, artillery and mortar strikes.It said that in the four cases detailed in its report, air strikes using powerful munitions had hit buildings full of civilians who had been staying there for long periods.It focused on the Aswad family, which it said lost eight members in a single air strike, the Hashish family, which it said lost 18 members, the Badran family which it said lost 39 members, and the Fayad family which it said lost 16 members."Witnesses reported that there were no fighters in the vicinity at the time of the attacks. Such attacks could be either direct attacks on civilians or civilian objects or indiscriminate attacks," the report said of the four cases studied, adding that such attacks amounted to war crimes.Amnesty called on the coalition and member states to acknowledge the scale of devastation, make public necessary information for an independent investigation and make reparations to victims.