The US has been working with Kigali and the ICC to transfer Bosco Ntaganda to the The Hague “as quickly as possible”.
US Assistant Secretary of State for African Affairs, Johnny Carson, said Rwanda was cooperating and would not interfere with the transfer of the man, also known as “The Terminator”.
"The timeline is uncertain but the need for rapid and quick action is clear," Mr Carson said, according to AFP.
Neither the US nor Rwanda recognise the ICC, but Carson said it was important that the transfer of Ntaganda from the embassy to the airport was “in no way be inhibited".
Ntaganda surrendered at the US embassy in the Rwandan capital on Saturday after being defeated by a rival faction within his M23 rebel group.