The beheading of US journalist Steven Sotloff by Islamic State militants is the latest in a series of war crimes being committed by the armed group across Syria and Iraq, Amnesty International said today.A video published online yesterday by the armed group calling itself the Islamic State (IS) showed Steven Sotloff, who was abducted in northern Syria in August 2013, being killed in the same manner as fellow US freelance reporter James Foley last month.“The execution of Steven Sotloff is a war crime, and it follows a pattern of other shocking atrocities carried out by the Islamic State in recent months,” said Philip Luther, Director of Amnesty International’s Middle East and North Africa Programme.“The world has rightly condemned the brutal deaths of Steven Sotloff and James Foley. These unjustifiable killings are, though, merely the tip of the iceberg when it comes to abuses by the IS in Syria and Iraq.”The killing of Sotloff, which US authorities today said they had “authenticated”, follows summary killings by the IS of hundreds, if not thousands, of others in the region this year. Victims include members of ethnic and religious minority communities, soldiers and policemen, as well as other journalists.Some 150 captured Syrian government army soldiers were killed after the IS took control of the Tabqa airbase, north-east Syria, on 24 August 2014.Dozens of other Syrians, including children, have been killed by the IS in public places already this year for a range of “crimes”.In Iraq, several hundred captured government soldiers were summarily killed in Tikrit after the IS seized the city in June 2014.The IS has also carried out summary killings targeting ethnic and religious minorities, including those of at least hundreds of Yezidi villagers in the Sinjar region in August 2014 – some in mass killings. “The killings of two US journalists in recent weeks increases the urgency to secure the release of those still held hostage by the Islamic State,” said Philip Luther.“Efforts must also be made to seek justice for the hundreds of other victims of the Islamic State’s crimes, and to protect the minority groups that remain most at risk from their attacks.”An Amnesty International briefing, Ethnic cleansing on a historic scale: the Islamic State’s systematic targeting of minorities in northern Iraq, published this week indicated that the IS has launched a systematic campaign of ethnic cleansing in northern Iraq.It documented war crimes that especially targeted ethnic and religious minorities, including mass summary killings and abductions.The ethnic and religious minorities targeted in northern Iraq include, in addition to members of the Yezidi faith, Assyrian Christians, Turkmen Shi’a, Shabak Shi’a, Kakai and Sabean Mandaeans. Many Sunni Arabs known or believed to oppose the IS have also been targeted in northern Iraq.