Beheaded aid worker's employer says 'barbaric' crime must be punished

The humanitarian aid group that employed David Haines, apparently beheaded by Islamic State militants, voiced outrage at the "barbaric crime" and stressed it should not go unpunished.

David Haines in the execution video of Steven Sotloff.

ACTED, the Agency for Technical Cooperation and Development based in Paris, said Sunday it was "deeply stunned and horrified by the heinous assassination" of Haines that the group "condemned with the greatest possible force".

Scottish-born Haines, 44, was taken hostage in Syria in March 2013 and ACTED said he was working in a team helping Syrian refugees in a camp for displaced people near the Turkish border.

"The horrible assassination of David, a humanitarian worker, goes against every humanitarian principle and affects the whole of the humanitarian community," said ACTED, who vowed to continue its work to aid suffering populations.

"This barbaric crime cannot go unpunished," added the group.

Before joining ACTED, an international relief charity, Haines had been involved in humanitarian work in the Balkans, parts of Africa and elsewhere in the Middle East.