The Rwandan government says it "will not shoulder responsibility for the bombing of internally displaced people's [IDP] camps around Goma" in the Democratic Republic of Congo.
It comes after the US State Department said the mortars that killed at least 16 people were fired from positions held by the Rwandan army and the M23 rebel group. Congolese media also reported that the mortars were fired from rebel-held positions.
Thirty other people were wounded when mortars hit Lac Vert and Mugunga IDP camps near the eastern Congolese city of Goma on Friday.
"The attempt by the US State Department... to immediately and without any investigation place blame on Rwanda for the loss of lives in the IDP camps is unjustified," a statement by the Rwandan government said.
"Rwanda will not shoulder responsibility for the bombing of the IDP camps around Goma, or the security and governance failures of the [DR Congo's] government."
DR Congo President Felix Tshisekedi cut short a visit to Europe following the attacks.
The Congolese army and the M23, which is widely understood to be backed by Rwanda, blamed each other for the attacks. Rwanda denies backing the M23.