The UN Security Council says it intends to impose sanctions against leaders of the M23 rebel movement in the Democratic Republic of Congo.
It said it would also target those who violate an arms embargo in DRC.
This week a UN panel of experts said Rwanda and Uganda were supplying M23 with weapons and other support - allegations those countries deny.
On Thursday, Rwanda was elected to a temporary seat on the Security Council.
M23 rebels have been fighting the DRC government since April.
The non-binding Security Council statement condemns the M23 militia for "all its attacks on the civilian population, United Nations peacekeepers and humanitarian actors, as well as its abuses of human rights, including summary executions, sexual and gender-based violence and large-scale recruitment and use of child soldiers".
It also expresses "deep concern" at reports that external support "continues to be provided to the M23 by neighbouring countries", and demands that such support "cease immediately".
In a report leaked on Tuesday, a UN panel of experts said M23 leaders received "direct military orders" from Rwanda's chief of defence staff, Gen Charles Kayonga, "who in turn acts on instructions from the minister of defence", Gen James Kabarebe.
The document built on a UN report published in June which accused Rwanda of supporting the insurgents.
Before Rwanda was elected this week to sit on the UN Security Council for two years from January, the DRC raised a formal objection to its candidacy.
But one of Kigali's UN diplomats said voters would not be swayed by the "baseless report".
The BBC's Barbara Plett reports from the UN that according to diplomats, there is no appetite on the Security Council to sanction the senior Rwandan officials accused in the report.
But there is concern both about the violence in eastern Congo, and the potential it holds for regional instability.
Rwanda is widely seen as having backed armed groups in the east of DR Congo as a way to fight Hutu rebels who fled there after the genocide of the 1990s.
It has been accused of using militias as proxies in an on-going battle for the region, which is rich in minerals. The Rwandan government strenuously denies the accusations.
The M23 rebellion started when a militia that had been absorbed into the Congolese army mutinied and went on the rampage in the eastern part of the country.
Since then nearly half a million people have been displaced by fighting between the M23 and the army.
Friday's Security Council statement called on the rebel group to allow "unhindered humanitarian access" to areas under its control.
Also on Friday, the Associated Press news agency reported that M23 had lead an attack on the army in eastern DRC earlier in the week, ending a recent lull in fighting.