KABUL, Afghanistan (AP) — The long-awaited transfer of the U.S. detention center in Afghanistan was delayed once again Saturday after a deal struck between the two governments broke down before the planned handover ceremony.

The delay suggests that the two sides have yet to resolve thorny issues such as whether Afghans can be held without trial and whether the U.S. will have the power to block the release of detainees it considers particularly dangerous. It also throws a pall over ongoing negotiations for a bilateral security agreement that would govern the presence of U.S. forces in Afghanistan after the current combat mission ends in 2014.