Friends and colleagues of a British journalist and international development worker who died in Istanbul have described her reported suicide as "impossible to understand".

Jacqueline Anne Sutton, known as Jacky, was found dead at Ataturk Airport after flying from London on Saturday night.

The 50-year-old was the Iraq country director for the Institute for War and Peace Reporting (IWPR), which said it was "devastated" at her death.

Ms Sutton was appointed to the role at the end of June following the death of her predecessor Ammar Al Shahbander, who was killed in a car bomb attack in Baghdad in May.

Anthony Borden, executive director of the IWPR, called for an "open and transparent" investigation into her death - which was reported as suicide by Turkish media outlets.

Mr Borden told BBC Radio 4's World at One programme: "I find this quick judgment being published almost the minute we learn of her death very impossible to understand. There's a matter of boot laces - I'm not even sure the boots she was wearing even had laces.

"One can never know what is in someone's heart and soul. But everything that everyone knew about Jacky was that she a very experienced professional. She had a very positive nature and outlook, and very significant work to get on with."

Several other people who worked with Ms Sutton have questioned reports she killed herself after missing a connecting flight and admitting she did not have enough money to pay for another ticket.

She had been in London to join Mr Al Shahbander's family, friends and colleagues at a memorial service held for him at St Bride's Church in Fleet Street last week and was due to catch a connecting flight from Istanbul to Erbil, Iraq, according to the IWPR.

Mr Borden said Ms Sutton's sister would be travelling to Istanbul with an IWPR employee to meet with British and Turkish officials.

He said: "She was extremely bright, highly competent, and well able to handle herself in difficult environments, and she was universally loved. We are in total shock."

Her employer said Ms Sutton had worked as a producer for BBC World Service from 1998 to 2000 and served with the United Nations in numerous senior roles that took her from Afghanistan and Iran to west Africa and Gaza.

Iraqi journalist Mazin Elias, who had worked with Ms Sutton, told MailOnline that it was "impossible" that she killed herself.

Mr Elias said "What I'm sure about, the kind of person that Jacky was, it's impossible she would have killed herself, impossible. She's really looking for a better life for everyone. So kill herself? That's crazy."

Ms Sutton was a "big manager" who was unlikely to have missed her flight, he added: "No, that's impossible ... we're not talking about a girl. She's a woman, an official woman, she's a big manager."

Mr Elias alleged that Ms Sutton could have been killed. "I'm really sad and sorry what happened, but if someone tells me 'she killed herself', I tell him: 'No, that's wrong, someone killed Jacky'," he said.

Ms Sutton, who spoke five languages including basic Arabic, had been studying for a PhD at the Centre for Arab and Islamic Studies at the Australian National University.