Muslims in Central African Republic (CAR) are being "butchered like sheep'' by Christian militias, and the deployment of French troops has not improved their safety, according to witness accounts from refugees arriving on evacuation flights to Mali.

On Thursday, a UN official identified "the seeds of a genocide" in CAR, unless the international response to the crisis is ramped up.

As he stepped off a five-hour flight in the Malian capital, Bamako, refugee Hissène Ibrahim, 21, said: "I was scared. I saw people killed in front of me and cut up like animals. They cut the hand off the Muslim and put it in his mouth. In that environment you end up thinking that if I stay here I am going to go crazy and become like these people who kill people."

Ibrahim, a student, said he and some 600 other Malian refugees who arrived in Bamako on flights this week had managed to escape CAR, thanks to a military escort to the airport. "We had left our homes last month and had been sleeping at the Senegalese consulate in (the capital) Bangui. There is no way Muslims can go anywhere near the airport by themselves because there are only Christians there. If you go there you will be chopped up in bits."

A French soldier from the Sangaris force watches over Central African Republic bush from a Puma helicopter. Photograph: Eric Feferberg/AFP/Getty Images

The diamond-rich former French colony descended into chaos last year after the Séléka Muslim rebel coalition seized power, unleashing a wave of killings and looting that in turn triggered revenge attacks by the anti-balaka (anti-machete) Christian militia.

The refugees said the resignation last Friday from the CAR presidency of Séléka founder Michel Djotodia, which had been seen as an appeasement measure, has unleashed a new wave of hatred against Muslims.

On Thursday, John Ging, director of operations for the UN Office for Co-ordination of Humanitarian Affairs, told a news conference in Geneva: "It has all the elements that we have seen elsewhere, in places like Rwanda and Bosnia. The elements are there, the seeds are there, for a genocide. There's no question about that."

Speaking from New York after her visit to CAR last month, US ambassador to the UN, Samantha Power said, "We are seeing a cycle of retribution and violence that is extremely alarming. It is a cycle that needs to be broken immediately ... NGOs report machete wounds, gunshot wounds to very very young children. Most of the patients who are turning up at hospitals, at least on the basis of hospital administrators and NGOs that we have spoken to, are turning up with knife, machete and gunshot wounds."

French ambassador Charles Malinas visits Bossangoa in the Central African Republic. Photograph: Eric Feferberg/AFP/Getty Images

Adamou Diabé, 32, arrived in Bamako with his mother, wife and four children. He said: "Muslims are being butchered like sheep. The resignation of the president made the problem worse. You felt that at any moment you could die because they (the Christians) were after us and neither the police nor the gendarmerie nor anyone in authority is working any more.

"I have close relatives who were killed because they wanted to cross into the Christian area. All they wanted to do was walk through. There were brothers also who were killed on the road to Bangui. They were accused of being Séléka when in fact they were just civilian Muslims," said Diabé who like most of the refugees was born in CAR.

Thousands of Malian migrant workers settled in CAR since before its independence from France in 1960. Traders and artisanal diamond miners, they married Central African women and established families. As a result, the majority of the refugees now arriving in Bamako have never set foot in Mali and do not speak any west African languages. Officials greeting them have to speak through interpreters.

The refugees said based on their experience the sectarian divide in CAR dates back at least two decades. Ibrahim said Malians in CAR had grown wealthy in the 1960s and 70s but their fortunes changed after the election of President Ange-Félix Patassé in 1993.

"Before, our parents worked with diamonds, as artisanal miners," one said. "Then came the time of President Patassé right up until President François Bozizé (deposed in 2013) and people no longer liked Muslims. Our parent became poor. They had to sell their villas. Buying a prospecting licence became really expensive for Muslims, whereas Christians were allowed to work."

More than 1,000 Malian refugees from CAR have arrived in Bamako in the past fortnight on four flights chartered by the Mali government and the International Organisation for Migration (IOM).

The IOM plans to evacuate migrant workers by air from CAR to Niger and Sudan. The organisation has launched an emergency $17.5m appeal to support the resettlement in their countries of origin of 50,000 Africans who need to be evacuated from the republic.

Ambassador Power added, "Those who survive the violence are crying out for justice, and unfortunately and in not seeing justice be done and continuing to see these armed groups on the loose and not held accountable for any atrocities that they carry out, we heard from people who are very tempted to try take matters into their own hands, and this is one of the reasons that more people over the last few months have joined onto armed groups is a desire for vengeance.

"So it is imperative that the transitional government demonstrate that there are consequences for committing human rights abuse, in the security council we strengthen the UN mission's ability to monitor human rights abuses, and we supported the secretary general's call for a commission of inquiry ... We are hopeful that this will help the transitional authorities identify perpetrators of atrocities and then of course bring them to justice"

There are nearly 1 million displaced people in the country and according to Power over half of the population – some 2.6 million – are in need of humanitarian assistance.

Over 100,000 people are thought to be in camps at Bangui airport where very few services are operating. EU foreign affairs ministers are due to meet in Brussels on Monday to vote on sending EU troops to CAR, and donors will review funding levels.

Meanwhile, the US military has started transporting the first elements of a Rwandan battalion to the Central African Republic, where they will join an African Union mission, the Pentagon said.

"We began today passenger movements for Rwandan forces from Kigali to Bangui," spokesman Rear Admiral John Kirby said.

Two C-17 cargo planes flew 70 Rwandan troops with vehicles and equipment on Thursday, Kirby said. They will be followed by a total of about 800 Rwandan soldiers and 70 vehicles over the next three weeks.

Additional reporting by staff and AFP.