THE Islamic State in Iraq and Syria (ISIS) has committed large-scale atrocities including mass executions against Shi'ite Muslims, ethnic minorities as well as Syrian and Iraqi government forces since the group overran large swathes of Iraq and Syria last summer.

But it is the group's executions of foreign captives, most of them Americans and Britons, as well as the filming and subsequent dissemination of the executions, that have sparked outrage worldwide.

Here is a list of who were killed, and when the killings were made known:

1. Aug 19, 2014 - United States journalist James Foley, 40

ISIS posted a nearly five-minute video online titled A Message To America that showed Mr Foley, dressed in an orange jumpsuit, reciting a short statement in which he calls the US government "my real killers", before he was executed.

Mr Foley, a New Hampshire native, was kidnapped in Syria in 2012 while on his way to the Turkish border, merely months after he was released from captivity in Libya in 2011.

His execution was the first by ISIS in retaliation against the launch of US air strikes against the group in Iraq two weeks previously. He had apparently converted to Islam while in captivity.

2. Sept 2, 2014 - US journalist Steven Sotloff, 31

A freelance reporter fluent in Arabic and described as having the "courage and that little bit of craziness" to work in war zones, Mr Sotloff had filed stories from Bahrain, Egypt, Yemen, and Libya before being kidnapped by ISIS in northern Syria in August 2013.

Mr Sotloff was filmed saying he was "paying the price" for the US intervention in Iraq with his life, before he was beheaded.

3. Sept 13, 2014 - British aid worker David Haines, 44

Mr Haines, a former military man who was described by his family as being "most alive" when doing humanitarian work, was kidnapped by ISIS in March 2013 - just 10 days after he began working for French non-governmental Agency for Technical Cooperation and Development - along with a colleague, Italian aid worker Federico Motka, near the Atmeh refugee camp in Syria.

In the footage of Mr Haines' killing, a hooded militant blames British Prime Minister David Cameron for joining forces with the US and says the alliance will drag the British people into "another bloody and unwinnable war".

Mr Motka was released later, after a ransom was paid.

4. Oct 3, 2014 - British aid worker Alan Henning, 47

A taxi driver said to have a heart of gold, Mr Henning skipped Christmas with his family in December 2013 to become the sole non-Muslim on an aid convoy travelling to northern Syria - only to be abducted within 30 minutes of crossing into the war-ravaged country.

"Because of our Parliament's decision to attack (ISIS), I - as a member of the British public - will now pay the price for that decision," Mr Henning was forced to say moments before his death, captured in a graphic clip lasting 1 minute and 11 seconds which was uploaded to YouTube.

He was killed despite the protests of leading Muslim clerics, including one of the top Al-Qaeda theorists.

5. Nov 16, 2014 - US aid worker Peter Kassig, 26

ISIS claimed to have executed Mr Kassig, a former US Army Ranger who risked his life to provide medical treatment and aid to those suffering from Syria's civil war.

In a 15-minute video, a militant stood over a severed head bearing a resemblance to Mr Kassig. The clip also showed the gruesome simultaneous beheadings of at least 18 men described as Syrian military personnel, the latest in a series of mass executions and other atrocities carried out by ISIS.

Mr Kassig was also known as Abdul-Rahman, a name he took after his conversion to Islam while in captivity. He was abducted on his way to the eastern Syrian city of Deir al-Zor in October 2013.

6. Jan 25, 2015 - Japanese freelance military contractor Haruna Yukawa, 42

Mr Yukawa's execution was announced by ISIS in a video that showed a man, identified as his friend and fellow captive Kenji Goto, holding a photo of his headless corpse. Mr Goto said in the video that Mr Yukawa was killed because Japan had failed to pay a US$200 million (S$268 million) ransom for the two hostages within a 72-hour deadline announced on Jan 20.

The sum was the same amount that Japan Prime Minister Shinzo Abe had pledged as non-military aid when he visited the Middle East last month.

By various accounts, Mr Yukawa was a troubled man whose business had failed and whose wife had died of cancer. He flirted with right-wing extremism and developed a fascination with weaponry and war, The Guardian said. He was travelling in Syria as a self-styled military contractor before being kidnapped in Aleppo last August.

7. Jan 31, 2015 - Japanese journalist Kenji Goto, 47

In a brief video released by ISIS, Mr Goto is seen kneeling, dressed in an orange jumpsuit, as a masked man standing beside him with a knife blames the Japanese government for his "slaughter".

ISIS had vowed to kill Mr Goto and Jordanian pilot Muath al-Kasaesbeh by sunset on Jan 29 unless Amman handed over an Iraqi female militant. Mr Goto's execution came after Japan said negotiations over the prisoner exchange had stalled.

Mr Goto disappeared last October after crossing into Syria on a personal mission to rescue his friend, Mr Yukawa.

8. Feb 2, 2015 - Jordanian military pilot Muath al-Kasaesbeh, 26

His death was made known when ISIS released a sleek, 22-minute video showing the brutal execution of the pilot, who was captured by the group last December after his plane crashed in Syria.

First Lieutenant Kasaesbeh was shown in the clip being burnt alive in a cage.

Jordanian state television said the airman had been killed a month before, on Jan 3, despite ISIS later demanding for Jordan to hand over a female Iraqi suicide bomber in exchange for his life.

SOURCE: The Straits Times' archives