Rwanda has threatened to withdraw co-operation with the United Nations if a draft report criticising its army is published.
Dismissing claims in the UN report as "insane", it says it will reconsider its contributions to UN peacekeeping missions.
The document accuses Rwanda's Tutsi-led army of killing Hutus in Democratic Republic of Congo in the 1990s - acts that it says may amount to genocide.
Extremist Hutus killed an estimated 800,000 Tutsis in Rwanda during 1994.
But the leaked UN draft report says that in the years following the genocide, the Tutsi-dominated Rwandan army went into neighbouring Zaire - now Democratic Republic of Congo - and killed tens of thousands of ethnic Hutus.
Strongly worded letter sent
It emerged on Saturday, the BBC reports, that Rwandan Foreign Minister Louise Mushikiwabo had responded to the report earlier this month, sending a strongly worded letter to UN Secretary-General Ban Ki-moon.
In the letter, obtained by journalists in the US, she criticised the sourcing and methodology of UN investigators.
She concluded: "Attempts to take action on this report - either through its release or leaks to the media - will force us to withdraw from Rwanda's various commitments to the United Nations, especially in the area of peacekeeping."
Rwanda contributes thousands of peacekeepers to the joint UN-African Union mission in the Sudanese region of Darfur, and the commander of the force is a Rwandan.
Analysts say the possible withdrawal of these troops would be a massive blow, especially as it comes at a time of increased violence in Darfur.
Rwandan officials have always said that their forces entered Zaire to pursue the Hutu militias responsible for carrying out the mass killings of Tutsis and that no civilians were killed.