The five Doctors Without Borders (MSF) staffers seized by an unknown group in northern Syria this week are Belgian, Danish, Peruvian, Swedish and Swiss nationals, the humanitarian organisation and media said Saturday.
Spokespeople from the various chapters of the group in four European countries confirmed the information regarding the MSF employees taken Thursday night from a house they were using in war-ravaged Syria.
The Peruvian foreign ministry meanwhile said it was working to confirm media reports there that the fifth MSF staff member taken was from the South American country.
"I can't give you any details for security reasons, but one of them is of Swiss nationality," MSF Switzerland spokeswoman Sibylle Berger told AFP.
MSF Denmark also said in a statement that "there is a Dane among the five relief workers," while MSF Sweden's spokeswoman Karin Ekholm confirmed that a Swede had also been taken Thursday evening.
"We haven't had contact with them since then," she said.
MSF has declined to provide further information about the staff members, not even providing their ages or saying whether they are men or women.
Belgian Foreign Minister Didier Reynders however told broadcaster RTL-TV that the Belgian national was a nurse in his 30s.
He emphasised though that it had not yet been established that the five had been kidnapped.
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"We do not have confirmation from other sources (besides MSF), so I want to make clear that I'm talking only about a possible kidnapping," he said.
It remained unclear who had taken the MSF staff and the organisation has so far refused to provide the exact location of the house they were taken from.
"We are still trying to analyse the situation and see what we can do to help our colleagues," Berger said, explaining why the organisation was being so tight-lipped.
In a statement Friday, the organisation said only that the five had been taken "apparently for questioning".
"MSF is in contact with all the appropriate actors as well as the families of the colleagues and is doing everything possible to reestablish contact with these colleagues," spokeswoman Samantha Maurin said in that statement.
MSF has six hospitals and four health centres in northern Syria and provides health support from neighbouring countries to within Syria as well as to Syrian refugees.
In September 2013, a Syrian surgeon working for the group was killed in the north of the country, and aid workers operating in rebel-held parts of Syria have faced detention and kidnappings.
In October, seven employees of the International Committee of the Red Cross were kidnapped in northwestern Idlib province, with a Syrian NGO blaming the abduction on the Al-Qaeda-linked Islamic State of Iraq and the Levant.
ISIL has been accused of targeting both foreign and Syria journalists as well as aid workers and activists for kidnapping.
Syrian rebels have in recent days declared war on ISIL, accusing the group of imposing a reign of terror on areas under its control.