( CNN ) -- Attempts to purge Muslims from parts of the war-torn Central African Republic have prompted `` a Muslim exodus of historic proportions , '' rights group Amnesty International warned Wednesday . International peacekeepers have `` failed to prevent the ethnic cleansing of Muslim civilians in the western part of the Central African Republic , '' the group said . Another rights group , Human Rights Watch , also warned Wednesday that the country 's minority Muslim population is `` being targeted in a relentless wave of coordinated violence that is forcing entire communities to leave the country . '' The Central African Republic , a former French colony , was plunged into chaos last year after a coalition of mostly Muslim rebels dubbed Seleka ousted President Francois Bozize . They have since been forced out of power , but Christian militias , known as the anti-balaka , which translates as `` anti-machete , '' have been allowed to fill the power vacuum , Amnesty International said , with dire consequences for Muslim civilians . `` Anti-balaka militias are carrying out violent attacks in an effort to ethnically cleanse Muslims in the Central African Republic , '' said Joanne Mariner , senior crisis response adviser at Amnesty International . `` The result is a Muslim exodus of historic proportions . '' The Amnesty International report said international peacekeepers in the country must do more to protect Muslim communities and rein in the anti-balaka militias . There are about 1,600 French troops on the ground , alongside about 6,000 soldiers from an African Union-led peacekeeping force , known as MISCA . Forcible expulsion . The rights group also said the backlash against Muslim civilians was foreseeable -- and should have been prevented . `` In power for nearly 10 months , the Seleka were responsible for massacres , extrajudicial executions , rape , torture , and looting , as well as massive burning and destruction of Christian villages , '' it said . `` As the Seleka withdrew , the international forces allowed the anti-balaka militias to take control of town after town . The resulting violence and forcible expulsion of Muslim communities were predictable . '' For its report , Amnesty International interviewed more than 100 people who witnessed attacks against Muslims firsthand . The worst violence documented was in the northern town of Bossemptele , where at least 100 Muslims were killed in January , it said . Among the dead were women and old men , including an imam in his mid-70s . Other northwestern towns where Muslims communities have been attacked include Bouali , Boyali and Baoro , it said . The spiraling ethnic violence in the Central African Republic has led some observers to fear another genocide like that seen in Rwanda nearly 20 years ago . Antonio Guterres , head of the U.N. refugee agency , said he has `` witnessed in the Central African Republic a humanitarian catastrophe of unspeakable proportions . Massive ethno-religious cleansing is continuing . '' He cited `` indiscriminate killings and massacres '' and `` shocking barbarity , brutality and inhumanity . '' He said he 's `` deeply distressed that nearly half a million Central Africans have been newly displaced since December alone . In all , 2.5 millions are in desperate need . '' He said the country is `` falling through the cracks of international attention '' and that ca n't be permitted . `` Tens of thousands of people are fleeing the country for their safety , many are trapped with nowhere to go . In Bangui alone , thousands of people are in ghettos in grave conditions , '' he said in a statement . He said the international community must act by deploying forces on the ground . `` It is imperative to re-establish security , law and order . For the people of the Central African Republic , safety and security for all is the most urgent priority , '' Guterres said . `` Acting in concert , particularly with the support of religious leaders , all actors must enhance mediation and pave the way for the restoration of peace and sustainable reconciliation . '' Human Rights Watch highlighted the language used by the anti-balaka militias -- which , it said , `` suggests their intent is to eliminate Muslim residents from the Central African Republic . '' `` At this rate , if the targeted violence continues , there will be no Muslims left in much of the Central African Republic , '' said Peter Bouckaert , emergencies director at Human Rights Watch . `` People whose families have peacefully lived in the country for centuries are being forced to leave , or are fleeing the very real threat of violence against them . '' Human Rights Watch cites the example of a gold trading center , Yaloke , which had an estimated Muslim population of 30,000 and eight mosques before the conflict . When the group visited the town last week , fewer than 500 Muslims and one mosque remained , it said . Fled into exile . The medical aid group Doctors Without Borders , or Medecins Sans Frontieres , last week also warned of `` extreme and unprecedented levels '' of violence against civilians as Muslim and Christian militia groups clash . `` Although the conflict is complex and all communities are affected by the violence , the minority Muslim community is increasingly targeted , '' the group said in a statement . `` In many towns , Muslim groups are isolated and threatened by anti-balaka forces while tens of thousands of Muslims have already left the country into exile in Chad or Cameroon . '' The African Union also raised concerns over violence toward Muslim civilians and Chadian nationals . The chief prosecutor of the International Criminal Court , Fatou Bensouda , said Friday that she was opening a new investigation into serious abuse allegations . `` In many incidents , victims appear to have been deliberately targeted on religious grounds , '' she said . Support for peacekeepers . A jointly penned column by Presidents Barack Obama and Francois Hollande , published Monday in The Washington Post , said the two nations were working together to confront the crisis , as the French leader pays a state visit to Washington . `` In the Central African Republic , French and African Union soldiers -- backed by American airlift and support -- are working to stem violence and create space for dialogue , reconciliation and swift progress to transitional elections , '' it said . The U.N. Security Council voted last month to continue its peacekeeping mission in the country and to authorize the use of force by European Union troops there . The decision came after the nation tapped Catherine Samba-Panza , mayor of the capital of Bangui , as its interim president . She replaced Michel Djotodia , the leader of the Seleka rebels who seized power in March only to step down in January after failing to halt the escalating violence . Last year 's coup was the latest in a series since the country gained independence in 1960 . CNN 's Nana Karikari-apau contributed to this report .
NEW : Head of the refugee agency ' deeply distressed ' Amnesty International says they have failed to stop ethnic cleansing . Violence has led to a ` ` Muslim exodus of historic proportions , '' says the rights group . Christian and Muslim militia groups are warring in the Central African Republic .