International Committee for the Red Cross says New Zealand nurse Louisa Akavi may well be alive, even though she has now been held longer than anyone in the history of the aid group.
A New Zealand nurse was abducted by the so-called Islamic State more than five years ago and is still missing, authorities have revealed as they make a plea for help in finding her.
Nurse Louisa Akavi was snatched along with Syrian drivers Alaa Rajab and Nabil Bakdounes while travelling in a Red Cross convoy delivering supplies to Idlib, in the northwest of the country.
Armed men stopped their convoy on October 13, 2013, and abducted seven people, four of whom were released the following day.
The International Committee of the Red Cross (ICRC) has kept Louisa Akavi's identity a secret until now, in a bid to keep her alive.
Last seen in 2018
A decision by the New York Times to publish a detailed story on Louisa Akavi's circumstances prompted the ICRC to release a statement.
Akavi, now 62, joined the ICRC in 1988 and worked in hotspots including Afghanistan, Bosnia, Iraq, Somalia and Sri Lanka.
After being moved by IS forces to Raqqa in 2017, she was seen in Al-Bukamal in late 2018, close to the Syrian-Iraqi border near the Euphrates River, the last concrete information on her whereabouts, the aid group said.
The New York Times reports the Red Cross was in particular buoyed by reports from at least two people who described seeing her in December at a clinic in Sousa, one of the final villages to be held by IS jihadists.
Some of the witnesses said they saw her performing medical duties at clinics and hospitals under IS control, indicating that she was no longer held in a cell and was able to use her nursing skills to win a modicum of freedom.
'Secret kept in hopes of positive result'
Dominik Stillhart, director of operations for the ICRC, said staying silent for five years has not been easy.
"We have not spoken publicly before today because from the moment Louisa and the others were kidnapped, every decision we made was to maximise the chances of winning their freedom," he told the New Zealand Herald.
"With that goal in mind, we have long decided not to share details in the hopes this approach would lead to a positive result. With Islamic State group (ISg) having lost the last of its territory, we felt it was now time to speak out."
But with victory declared over IS weeks ago, her whereabouts are still unknown and the International Committee of the Red Cross have made an appeal for information that could help find Louisa, Alaa and Nabil.
"Our latest credible information indicates that Louisa was alive in late 2018," the ICRC said in a statement.
"Following the fall of the last territory held by Islamic State group, we fear there is an extra risk of losing track of Louisa, though we remain hopeful this period will instead open new opportunities for us to learn more about her whereabouts and well-being."
'Difficult time for families'
Akavi has now been held longer than anyone in the Red Cross' 156-year history.
"The past five and a half years have been an extremely difficult time for the families of our three abducted colleagues," said Dominik Stillhart.
"Louisa is a true and compassionate humanitarian. Alaa and Nabil were committed colleagues and an integral part of our aid deliveries.
"We call on anyone with information to please come forward. If our colleagues are still being held, we call for their immediate and unconditional release."
Akavi had carried out 17 field missions with the ICRC and the New Zealand Red Cross, the statement said. Rajab and Bakdounes were "dedicated husbands and caring fathers", it added.
New Zealand deploys special forces as part of search
New Zealand Foreign Minister Winston Peters said his government was still working on the basis Akavi was alive, and had during the five-year period deployed a non-combat Defence Force team to Iraq to search for Akavi in Syria.
"We have now reached a point where all the territory once held by ISIS has been liberated. Unfortunately, the current whereabouts of Louisa is unknown," he said in a statement.
"However, the New Zealand government continues to work tirelessly to locate her and bring her to safety."
Mr Peters said there are ongoing operations to locate her, including the deployment of a small multi-agency team based in Iraq.
"This has involved members of the NZDF (New Zealand defence force) drawn from the Special Operations Force, and personnel have visited Syria from time to time as required," he said.
"This non-combat team was specifically focused on locating Louisa and identifying opportunities to recover her."
Since 2014, New Zealand and some international news organisations have held an agreement with the New Zealand government and the Red Cross to not make Akavi's abduction public, with fears it could make her situation worse.
Syrian war makes search difficult
The war in Syria, which began in 2011, has claimed more than 370,000 lives and forced millions of people to flee their homes.
The Kurdish-led SDF, backed by a US-led coalition, captured the last IS bastion in eastern Syria on March 23, and had detained thousands of suspected IS fighters.
But this could make it more difficult to find Akavi.
"We are speaking out today to publicly honour and acknowledge Louisa's, Alaa's, and Nabil's hardship and suffering," the ICRC statement said.
The organisation has 98 foreign workers and 580 Syrians working in the country.
The Syrian Observatory for Human Rights accuses IS of abducting thousands of people since 2014.
Additional reporting: AFP, AAP.