Rwanda's army has warned neighbouring Democratic Republic of Congo, who it accuses of deliberate bombing over the border, that it will not stand by "indefinitely", it said in a statement late Friday.

On Thursday, Rwanda accused Congolese troops of firing a rocket over the border into Bugu village, while on Friday afternoon it said five mortar bombs landed in the Rwandan villages of Bukumu, Kagezi, Kageyo and Rusura.

"The RDF (Rwanda Defence Force) remains prepared to take all necessary measures to ensure the safety of the population," Rwanda's army spokesman Joseph Nzabamwita said in a statement.

"Acts of provocation that endanger the lives of Rwandan citizens will not remain unanswered indefinitely," he added, but stressed that Kigali "remains committed and active in the search of a sustainable solution".

The bombings came amid fresh clashes outside the eastern DR Congo flashpoint city of Goma between the Congolese army, United Nations troops fighting alongside and the M23, a Congolese rebel group Rwanda is accused of backing. Rwanda denies the charge.

The M23 is made up of Congolese Tutsi who were integrated into the army following a 2009 peace accord. They mutinied in April 2012 saying the accord was never implemented.

In a tit for tat exchange, Kinshasa's government has in turn accused Rwanda of firing rockets on Goma on Thursday to help the M23, claims Kigali denies.

The latest unrest erupted in mid-July and ended an almost two-month truce between M23 rebels and government forces.

"The nature and pattern of these shelling suggests that they are not occurring accidentally," Nzabamwita said.

"The continued indiscriminate bombing of Rwandan villages by DRC armed forces is unacceptable and must stop immediately."