Ukraine's pro-Russian rebel leader Alexander Zakharchenko said Saturday that insurgents had released two US aid workers detained for alleged spying.
"We have freed two Americans that we arrested earlier. One of the two is a CIA agent, the other was enlisted," Zakharchenko told journalists, without giving further details.
The two men are believed to have been working for the International Rescue Committee (IRC) NGO in war-torn east Ukraine.
IRC head David Miliband released a statement saying that two of the organisation's workers who had been detained by the rebels some 10 days ago were now in a safe location, the BBC reported.
"The two remaining staff members were let go Friday, May 8th. By all accounts, they are healthy, out of harm?s way and eager to return to their loved ones," the former British foreign minister said in the statement.
The IRC said 37 of its workers were detained after separatists raided their offices in Donetsk on April 29.
Of those held 30 were local hires while seven were from outside Ukraine.
Five of the detained foreign staff were immediately expelled, while the other two were held in captivity for over a week.
"Every day, the world's humanitarian workers show great courage, taking risks help the most vulnerable in crisis situations. They should never be targeted," Miliband said in the statement.
The IRC has now suspended its work in Ukraine, he said.
At the time of the raid, rebel commanders said that they had discovered listening devices in the organisation's office.
"This is the first diplomatic scandal for our republic. All the devices were seized and handed over to the American authorities," Zakharchenko said.
A spokesman for the US embassy in Kiev said that they did not have any information on the release of the Americans.
Ukraine and the West accused Russia of masterminding the brutal separatist conflict in east Ukraine that has killed over 6,200 people in just over a year.
The IRC said that its operations were aimed at supplying "food, medicine and psychosocial support" to thousands of Ukrainians.