One monitor was freed Sunday after pro-Russian separatists seized a group of eight European monitors with the Organization for Security and Cooperation in Europe (OSCE) in eastern Ukraine earlier this weekend.

From CNN:

Pro-Russian separatists holding a European military observer team in eastern Ukraine released one of the observers for medical reasons Sunday, shortly after parading them before cameras, officials on both sides of the dispute said.

At least seven of the inspectors from the Organization for Security and Co-operation in Europe appeared at a news conference staged by the self-declared mayor of Slavyansk, Vyacheslav Ponomarev, who referred to them as “prisoners of war.”

The freed observer was from Sweden and had been suffering from diabetes, Ponomarev spokeswoman Stella Khorosheva told CNN. And Michael Bociurkiw, an OSCE spokesman in Kiev, the Ukrainian capital, called it “a welcome development.”

Holger Schmuck, one of the German members of the team, said earlier that their captors had ensured the ailing observer had all the water and sugar he needed and were taking particular care of him.

The monitors were seized Friday outside Slavyansk, one of the flashpoints in the standoff between Ukraine’s interim government and pro-Russian factions challenging its authority in the east. They said that although they have diplomatic status, they went along with Sunday’s news conference because the mayor asked them to.

The bus on which the group was traveling earlier was reportedly commandeered and driven to the headquarters of the separatists in Slovyansk, according to a Wall Street Journal report earlier this weekend.

Reuters reported Saturday that the separatists suspected the monitors of spying, and offered to release them in exchange for prisoners.

Vyacheslav Ponomaryov, de facto mayor of Slaviansk, told reporters: “They were soldiers on our territory without our permission, of course they are prisoners.”

He said the separatists were ready to exchange the captured monitors for fellow rebels now in the custody of the Ukrainian authorities.

“Prisoners have always been coins to exchange during times of war. It’s an international practice,” he said.

Ukraine’s state security service said the OSCE observers – part of a German-led military verification mission deployed since early March at Kiev’s request – were being held “in inhuman conditions” and that one needed medical help.

CNN reports however that there has been no evidence presented to support the separatists’ claimed suspicions of the monitors.

Ponomarev has accused the monitors of being spies for NATO and said he might exchange them for pro-Russian activists held by Kiev, but it is not clear if that would be a basis for any negotiations. No evidence has been produced to support any claim they strayed outside their mission.

One OSCE mission in Ukraine is tasked with helping to implement an international agreement signed April 17 in Switzerland, which called for illegal militia groups to disarm and leave occupied buildings, among other provisions. However, the abducted inspectors were working in the restive eastern Donetsk province under the mandate of a previously agreed OSCE mission.

Meanwhile, White House officials said on Saturday that the U.S. and G-7 allies will impose additional sanctions against Russia as early as Monday, reported the Washington Post.

Video report below from Euronews.

UPDATE 5/3/2014: the abducted military observers were freed in east Ukraine today.

[Featured image: video from The Telegraph]