Recurring tensions between the DRC and Rwanda flared anew last month amid violent clashes near the joint border, which have accused each other of supporting armed groups and even, in recent days, of launching cross-border strikes.

The UN on Saturday urged all parties in the conflict to "immediately cease all forms of violence", adding that "we reaffirm or strong commitment to the sovereignty, independence, unity and territorial integrity of the DRC and strongly condemn the use of proxies."

On Monday, Rwandan government spokeswoman Yolande Makolo hit out at MONUSCO, accusing it of being biased in Kinshasa's favour.

"When the DRC bombs Rwandan territory unprovoked, this is a serious matter that has consequences, and it has to stop once and for all.

"The UN force, MONUSCO, cannot be part of this aggression, or stand by and watch it happen as has been the case, otherwise they become complicit," she said on Twitter.

"By taking sides in this conflict, MONUSCO has contributed significantly to the intransigence of the DRC Government in cross-border shelling of Rwandan territory," she added.

Since late May, eastern DRC has been the scene of heavy fighting between the Congolese army and the M23 rebel group, a primarily Congolese Tutsi group, and just one of more than 120 armed groups that roam eastern DRC.

Kinshasa accuses Rwanda of supporting the M23, an allegation Kigali has repeatedly denied.

The two countries have recently traded tit-for-tat accusations of cross-border strikes.

Rwanda's defence ministry on Friday said the DRC's army fired two rockets into its territory.

The DRC in turn said Rwandan forces had bombed a school in its territory, killing two children in what it described as a "war crime" and "crime against humanity."

Contacted by AFP, spokeswoman Makolo rejected the accusations, describing them as "false and dangerous".

"Despite repeated provocations... Rwanda has not retaliated. There has been no shelling from Rwanda to the DRC, the ongoing fighting there remains an internal matter," she said Monday.

Relations between the two countries have been tense since the arrival in the eastern DRC of thousands of Rwandan Hutus -- the ethnic group accused of killing hundreds of thousands of Tutsis during the 1994 Rwanda genocide.

A thaw in the relationship followed the 2019 arrival of Felix Tshisekedi as DRC president, but tensions have sharpened again since last month.