The International Criminal Court (ICC) has been accused of "gross complacency or worse" towards Nigeria, where an Islamist insurgency has left thousands of Christians and other Nigerians dead.
The ICC has spent the last 10 years investigating claims of war crimes in Nigeria by Islamist faction Boko Haram as well as Nigeria's own security forces, but investigations remain in the preliminary stage.
In a letter to the ICC, human rights organisation PSJ UK is demanding a quick resolution after an "agonisingly long wait" for justice.
Recent figures from the International Committee on Nigeria suggest that 100,000 Nigerians have been killed by the Islamic State, Boko Haram or militant Fulani herdsmen since the year 2000.
Human rights barrister Paul Diamond, who supported PSJ UK's letter, said: "During this time period, deaths resulting from militant Fulani attacks include 17,284 across Nigeria and 13,079 in predominantly Christian states such as Benue, Kaduna, Plateau, and Taraba. That means three of every four militant Fulani victims during this time were Christians, not incidental by any means when reviewing genocide allegations."
In a letter to the ICC, PSJ UK warns that with each passing year, tens of thousands more people are dying.
"It is encumbent on the Court to take such allegations seriously and not prolong what has already been an agonisingly long wait for justice in Nigeria," the letter reads.
"Corruption must be rooted out as and when it is found, without prejudice to an abuser's status or reputation. The people of Nigeria, heavily burdened by Boko Haram's war crimes, famine, disease, Covid-19 and its economic effects on the prospects for employment, should not also have to contend with a corrupt and harmful national security force."
Ayo Adedoyin, PSJ UK Chief Executive, said: "We have to ask serious questions of the ICC after its dire handling of the situation in Nigeria. As a Court, it wields enormous influence on Nigeria's Government, world leaders and the private sector, all of whom can do something to stop the slaughter, yet it has failed abysmally.
"PSJ UK has written to the ICC with an ultimatum. We demand that clear and definite rulings of Islamist violence and government corruption permitting such violence, which is growing for all to see, are made imminently. Too many lives are at stake to waste time or resources on the case any longer.
"Nigeria's military, and parts of the police as recent 'End Sars' protests have shown, are not immune to corruption and war crimes, not to mention Boko Haram. The sooner this corruption can be detected, the sooner it can be decisively rejected."