A senior US official has warned Rwandan officials that they may face charges at the International Criminal Court for their support to rebels in eastern Congo led by warlord Bosco Ntaganda, who is wanted by the ICC on war crimes charges.

Stephen Rapp, the US Ambassador-at-Large for War Crimes Issues and head of the Office of Global Criminal Justice, told The Guardian that Rwandan authorities could be charged for “aiding and abetting” war crimes, like the former Liberian president Charles Taylor, who was convicted to 50 years in prison in may for his support to rebels in neighboring Sierra Leone.

“There is a line that one can cross under international law where you can be held responsible for aiding a group in a way that makes possible their commission of atrocities,” Mr. Rapp told The Guardian.

Mr. Rapp, who investigated the war crimes committed by armed groups in Sierra Leone in the late nineties, said comparing the former Liberian president to Rwandan President Paul Kagame that ”Charles Taylor never set foot in Sierra Leone, and aided and abetted, and was convicted of aiding and abetting.”

The warning comes less than a week after the United States announced it was cutting military aid to Rwanda because of the support to the M23 rebels in eastern Congo.

It is a further sign that Rwandan President Paul Kagame might finally be losing the unwavering support he had enjoyed in the past from the United States, despite evidence provided for more than a decade by UN reports, rights groups and the Congolese government that Rwandan authorities have been fueling wars in eastern Congo by providing weapons, men and ammunitions to rebel groups involved in atrocities.

“We have a lot of influence with the Rwandans. We've been very supportive of them. We're prepared to speak frankly to them as we have privately in the past, and now publicly,” Mr. Rapp told The Guardian.

“M23 was reinforced by Rwanda, and that has to stop. And that's the message we're delivering.”