One of the eight European observers being detained by pro-Russian separatists in the eastern Ukraine city of Slaviansk was escorted to an Organisation for Security and Cooperation in Europe (OSCE) vehicle and driven away.
The man was brought to the city administration by masked separatists and later walked out escorted by three unarmed men, got into a white OSCE jeep and drove off. The group declined to answer reporters' questions.
The observers, from Germany, Denmark, Poland and the Czech Republic as well as Sweden, were accused by their captors of spying for NATO and using the OSCE mission as a cover.
More top news
A nurse trying to identify a badly wounded hit-and-run victim suffered heartbreak when she discovered it was her own brother.
So-called Islamic State has blown up yet another monument in the ancient city of Palmyra, activists say.
Four people will go on trial in connection with the murder of teenager Becky Watts.