The deputy president has urged for patience in the face of delays in the repatriation of bodies.
At least 115 people, most of them South African, died when a church building collapsed in September.
The accord for the release of the girls has been called into question since it was announced.
Govt says all processes are being handled by Nigerian authorities.
The blast is likely to be blamed on Boko Haram militants, casting doubt on the recently signed ceasefire pact.
A family has accused govt of failing to communicate with them about the repatriation of victims.