Below is a list of previous executions of westerners by jihadist groups since 2002, after the reported death in Syria of American journalist Steven Sotloff whose beheading has been claimed by the ultra-radical Islamic State.

A propaganda video apparently showing the ghastly execution was released Tuesday, with IS stating the killing was in response to US air strikes against its positions in Iraq.

US officials were working to authenticate the footage, which if confirmed would mark the second IS video of a beheaded American in as many weeks.

Sotloff, well-versed in the history and culture of Islam and the Middle East, went missing August 4, 2013.


-- AMERICANS --

- January 23, 2002 - PAKISTAN: Reporter Daniel Pearl, working for The Wall Street Journal and researching a story about Islamist militants, is kidnapped in the southern city of Karachi and beheaded.

A graphic video showing his decapitation is delivered to the US consulate a month later.

- October 28, 2002 - JORDAN: Diplomat Laurence Foley, responsible for the US development agency USAID is shot at close range outside his Amman home.

Jordanian Abu Mussab Zarqawi, the head of the Al-Qaeda terror network in Iraq, is in 2004 sentenced to death in his absence for the killing. He is killed in 2006 in an American raid north of Baghdad.

- May 11, 2004 - IRAQ: A video shown on an Internet site linked to Al-Qaeda shows the beheading of businessman Nicholas Berg, who was abducted early April in Baghdad.

According to US security forces, the masked executioner is Zarqawi.

- June 18, 2004 - SAUDI ARABIA: An Islamist Internet site disseminates photos of the beheading of American aeronautical engineer Paul Marshall Johnson, who had been abducted several days earlier in Riyadh.

On August 19, 2014, a Riyadh court sentences an Al-Qaeda member to death and imposes jail terms of four to 30 years on 13 co-defendants for the crimes.

- September 20, 2004 - IRAQ: A particularly hardline group, led by Zarqawi, announces the decapitation of Eugene Armstrong, an American kidnapped September 16 in Baghdad, with one of his compatriots Jack Hensley and Briton Kenneth Bigley.

Hensley's execution is announced a day later.

- August 19, 2014 - IRAQ/SYRIA: Islamic State, the extremist group marauding across Iraq and Syria, posts a video of the decapitation of US journalist James Foley, 40, who was seized in northern Syria in November 2012.

One day later US officials announce there had been a failed earlier bid to rescue American hostages in Syria.


-- BRITONS --

- October 8, 2004 - IRAQ: The execution of engineer Bigley is announced, three weeks after his abduction by Zarqawi's group.

- June 3, 2009 - THE SAHEL: The North African branch of Al-Qaeda, AQIM, claims its first execution of a western hostage, Edwin Dyer, kidnapped on January 22 in the border area between Mali and Niger.

The tourist was in the hands of the group of Algerian Abdelhamid Abou Zeid, who several witnesses say cut Dyer's throat himself.


-- FRENCH --

- April 19, 2010 - NIGER: Michel Germaneau, a retired French engineer, 78, is abducted in northern Niger and taken to Mali by AQIM, which announces his execution on July 25 after a failed Franco-Mauritanian raid to liberate him.

Seven members of AQIM are killed in the raid.

- November 24, 2011 - MALI: Philippe Verdon is kidnapped from his hotel in Hombori in northeastern Mali. On March 20, 2013, AQIM announces that it has killed Verdon, in response to France's intervention in the country. The autopsy reveals that he was shot in the head.


-- ITALIANS --

- April 14, 2004 - IRAQ: Italian security guard Fabrizio Quattrocchi is shot at point-blank range, two days after his abduction, to punish Italy for refusing to withdraw its soldiers from Iraq.

He becomes the first foreign hostage killed in Iraq.

- August 20, 2004 - IRAQ: Italian journalist Enzo Baldoni is abducted on the road between Baghdad and Najaf. His filmed execution is claimed August 26 by a group calling itself the Islamic Army in Iraq.

- April 15, 2011 - GAZA STRIP: Vittorio Arrigoni, a pro-Palestinian militant, is found hanged in a house in the Gaza Strip several hours after having been taken hostage by a salafist-jihadist group.


-- POLE --

- February 7, 2009 - PAKISTAN: Polish geologist Piotr Stanczak is beheaded after having been held for more than four months by Islamist militants in northwestern Pakistan. (AFP)