The release of three hostages held by Marxist rebels in Colombia has been delayed, the Venezuelan envoy coordinating the handover said Sunday.

"We still don't know where in Colombia the liberation of the three hostages will take place," said Venezuelan Interior Minister Ramon Rodriguez Chacin, chief interlocutor in talks to free the captives.

The delay was the latest setback to international efforts to retrieve the hostages held by the Revolutionary Armed Forces of Colombia (FARC).