In short, just what the headline says, one of the prisoners is from Yemen. That rules out a Balkan connection. The other from Tajikstan, former USSR I think.
U.S. Transfers Two Guantanamo Detainees To Serbia
Two detainees at the U.S. military prison in Guantanamo Bay, Cuba, are being transferred to Serbia -- leaving 76 detainees at the facility.
Officials from the U.S. State Department and the Pentagon on July 11 confirmed that the transfers were taking place.
A State Department official named the detainees as Muhammadi Davlatov of Tajikistan and Mansur Ahmad Saad al-Dayfi of Yemen.
More At: http://www.rferl.org/content/us-guantanamo-detaines-transfer-serbia/27852255.html