A group of Western journalists were briefly seized by pro-Russian forces in the town of Slovyansk on May 2.
American reporters for CBS television news and the online site Buzzfeed, and a team with Britain's Sky News were detained at rebel-held checkpoints as they tried to enter the city.
The CBS reporter, Clarissa Ward, said that she and her colleagues were taken to different locations, and at one point blindfolded.
A male member of the team was beaten by the militants.
Buzzfeed's Mike Gigilo said the militants stole his jacket and helmet before eventually setting the journalists free.
Ukrainian forces have launched a major offensive to retake Slovyansk, which has been under the control of pro-Russian forces since April.
Several Ukrainian journalists, officials and ordinary citizens have gone missing in Slovyansk in recent weeks.
Based on reporting by AFP and huffingtonpost.com