The husband of a British-Canadian gunned down in Afghanistan claims her killers knew she was from an aid organisation.

Dr Jacqueline Kirk, a University of Ulster research fellow, was one of four International Rescue Committee workers killed on Wednesday when their car was ambushed in the Logar province.

She died alongside 30-year-old Nicole Dial, from Trinidad and Tobago, IRC driver Mohammad Aimal, 25, from Kabul and a thus far unnamed woman from Canada.

Dr Kirk had wide experience working with aid organisations such as Unesco and Unicef in troubled areas of the world such as the Lebanon, Rwanda, Angola, Ethiopia and southern Sudan.

Her husband Andrew Kirk, a research scientist, said: "They were travelling in white Toyota Land Cruisers that were clearly marked as IRC vehicles, as humanitarian vehicles.

"Their policy was never to travel with weapons in the car so there wouldn't be any doubt that they're a peaceful humanitarian organisation."

Dr Kirk was affiliated to the Ulster University's International Conflict Research centre, based at its Coleraine campus, but had been living in Montreal.

Professor Alan Smith, who worked with her for six months in 2005, said: "She was not a naive or reckless person.

"She was always respectful to local customs and very attentive when listening to people's views. We are all in a complete state of shock. She had a incredible commitment to humanitarian issues and was a wonderfully sensitive and dedicated person."

George Rupp, president of the IRC, said he and his colleagues were stunned and profoundly saddened by the deaths.

"These extraordinary individuals were deeply committed to aiding the people of Afghanistan, especially the children who have seen so much strife. Words are inadequate to express our sympathy for the families and loved ones of the victims and our devoted team of humanitarian aid workers in Afghanistan."

The IRC, based in New York, has suspended operations in Afghanistan indefinitely in the wake of the attack.

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