Court spokeswoman Edita Pejovic declined to reveal the identities of the detainees.
The U.N. war crimes court in The Hague has already charged 19 people in connection with the massacre.
Six of these have been convicted and 10 others, including ex-Yugoslav President Slobodan Milosevic, are on trial or awaiting trial.
The massacre's alleged masterminds, the Bosnian Serb wartime leader Radovan Karadzic and his military commander Ratko Mladic, remain at large.
(Reuters)