Pro-Russian militants held eight Ukrainian and one Swiss Red Cross workers hostage for seven hours in the rebel eastern Ukrainian city of Donetsk, beating one before freeing them early on Saturday, a Red Cross official said.
A spokesman for the self-styled Donetsk People's Republic, which held a referendum on Sunday on breaking with Kiev, said the workers had been detained on Friday evening by rebel activists on suspicion of espionage.
He could not clarify the nature of the accusations leveled against them or say where they had been held.
Jacques Barberis, deputy head of the International Red Cross mission in Ukraine and a Swiss national, said that he was in the group of nine volunteers from Donetsk and Kiev arrested in the Red Cross building in Donetsk.
Barberis said one person was beaten by militants. "I can confirm one [person] was beaten, he is now at home … others are well," he told Reuters by phone.
The treatment of the others from the group was "not bad," Barberis said, adding he and volunteers from Kiev should return to the Ukrainian capital by midday on Sunday.
Red Cross headquarters in Geneva said simply that there had been "some kind of incident last night."
Another Ukrainian Red Cross official in Kiev who asked not to be named, said that the institution had sent a report about the event to the Interior Ministry. He did not elaborate.
The Donetsk-based Novosti Donbassa website said the hostage-takers had also seized large stores of medicine from the Donetsk office.
The Red Cross website said medication had been delivered on May 7 to Donetsk head office for distribution in the region, where there has been heavy fighting in recent days between pro-Russian militants and Ukrainian security forces.