The Observer's Mark Townsend journeys into the remote and dangerous north of the country, into the heart of the rebel stronghold, to uncover fresh allegations of summary executions, disappearances and mass rapes guardian.co.uk

It was dusk when armed Seleka rebels dragged the teenager from the road leading north towards Kobe. They pulled her into the jungle and raped her for several hours. She was abandoned near Route Nationale 10 and, after stumbling into the town of Kaga-Bandoro, was taken to hospital. "There were five of them raping her until they tore her vagina. Her family paid the [hospital] expenses until she got well," said her friend, Lisa Moussa, 17.

Moussa was more fortunate. As soon as she saw the rebels, she began running. They tried to kill her, shooting until she stumbled and fell. The gang caught her and frogmarched her to a police station and threatened to rape her until her father paid 6,000 Central African francs (£7.90) for her release.

Lisa Moussa from Kaga-Bandora. Photograph: Mark Townsend

Moussa lives in the Camp Fleur district of Kaga-Bandoro, a town deep in the jungle of the CAR, which was tipped into anarchy when the Seleka rebels overthrew the government and seized power four months ago. The UN has declared the entire 4.6 million population to be victims and the country among its most dangerous destinations. Its refugee agency has called it the "most neglected crisis in the world". Médecins Sans Frontières warns that the country had been effectively "abandoned to its fate".

Although lootings and killings have been widely documented in the capital, Bangui, reports detailing the extent of the atrocities being committed in the country's vast hinterland remain scant, particularly in the north, where the Seleka uprising began.

Roads are impassable due to banditry and the rainy season. Kaga-Bandoro, 300km north of the capital, can only be reached via a mud airstrip, landing straight into a rebel stronghold where the rule of law has collapsed completely. Evidence of human rights abuses in the far north are clear. Seleka rebels have repeatedly mass-raped the region's women, say locals. Women are said to have been killed for refusing to have sex or surrender their food. Men have been summarily executed, tortured or have simply disappeared, witnesses say. Children have been recruited and, according to witnesses, provide a substantial proportion of the armed gangs. The Seleka rebels, it seems, are becoming more numerous and more violent. In the remote north, war crimes against civilians continue to be committed.

Events in Kaga-Bandoro were not only foretold but could have been prevented. Yet the international community refused to heed the escalating security warnings or answer requests for increased humanitarian funding. Europe's arms companies, with Britain a principal player, continued to flood the country, which has the world's second-lowest life expectancy, with military hardware.

Philippe Benezo whose daughter lost her baby because they could not reach the hospital quickly. Photograph: Mark Townsend

Even inside Kaga-Bandoro's hospital they were not safe. The Seleka stormed the grounds in mid-April and, according to hospital worker Henrietta Kiringuinza, 44, began raping patients. Staff fled as the rebels destroyed the hospital's three ambulances and looted everything, including lamps, refrigerators, medicine – even hospital beds. Farmer Philippe Benezon, 63, recently carried one of his six daughters, who was heavily pregnant, 10km from the village of Botto to the hospital. "There was no ambulance. We were bringing her by foot, but her baby died on the way. When we got to the hospital they took the baby from her belly."

Women appear to be the main target of the rebels. "Most of the time women are the victims of the atrocities. They attack them, sexually abuse them, rape them," said Thibault Ephrem, 25, who lives in Kaga-Bandoro. He had heard that women who refused their advances had been hacked to death with machetes. "If they want them or to get food and the woman says no, then she can be killed."

Dusk. Most attacks occur at night with Seleka revels preying on women and girls. Photograph: Mark Townsend

The Seleka seem to attack most frequently at night, prowling the streets of Kaga-Bandoro to abduct women and girls. "In our Abdala neighbourhood, if you go anywhere late at night when you are on your way back home they capture you or shoot you," said Moussa.

Kiringuinza said the rebels would melt away, only to suddenly return, beating people randomly and shooting throughout the night so "we are unable to sleep". Albert Vanbuel, the town's Catholic bishop, said Kaga-Bandoro's 26,000 population were trapped in a state of terror. Vanbuel says they have been utterly abandoned by the international community, allowing the Seleka to commit war crimes against civilians with impunity.

"There is nobody to help the population. There are no authorities, no militaries. When you resist, they kill you," he said.

It is impossible to verify how many people have been killed in Kaga-Bandoro, though Vanbuel believes the figure to be between 50 and 100. Ephrem says he knows of about 100, pointing to a looted petrol station whose owner was dragged on to the forecourt and shot. Benezon described how men were shot in the chest at close range and tortured. He had found bodies killed by the rebels, but how many lie undiscovered in the jungle is unknown. Similarly, how many have disappeared, taken into the jungle to never return, is impossible to ascertain. "We don't see them again, they just take them," said Vanbuel, who believes 60,000 of the region's 130,000 may now be hiding in the jungle.

Marguerite Mallot, 57, says attacks by Seleka rebels are ongoing and violent. Photograph: Mark Townsend

It is also unclear how many have perished from illness, succumbing to a diet of roots and the leaves of manioc plants. At night the tens of thousands decamped within the jungle are impossible to locate – the CAR is regarded as the least light-polluted country in the world, its darkness due to its lack of development. By day, the exodus has rendered Kaga-Bandoro strangely silent. Outlying villages lie deserted, torched to the ground. Even the sprawling UN compound 3km from the town has been looted, its food stores pillaged. Mother of seven Marguerite Mallot, 57, said: "They burned my son's house that he uses for selling some things, everything is burned."

Attacks continue. "They are still taking people's sheep, food and any other stuff by force. If you try to say anything, they point a gun at you," added Mallot. "They break into your house and take your stuff and if you say anything they beat you and tie you up," said Kiringuinza.

Anyone whose task was to monitor events in the CAR knew the atrocities were close to inevitable. The UN security council was first briefed last December over a rebel offensive involving a coalition called Seleka operating from the settlements north of Kaga-Bandoro. During the next six months it would be briefed seven times over Seleka's evolving threat. No effective action was agreed.

In the UN field office in Bangui, however, officials were becoming acutely concerned over the effectiveness of a plan to pay off fighters who agreed to disarm. Exactly one year – on 14 December 2011 – before the UN security council received its initial assessment on Seleka, officials in Bangui told the security council that a lack of funding to complete the disarmament process could push the country "to the brink of disaster".

On 4 April 2012, and evidently starting to panic, the UN office in the republic hastily organised a donors' conference. According to a security council report pledges were made by just two countries: Luxembourg offered £67,000 and Australia £134,000, despite £14.2m being required to complete the disarmament and reintegration process.

When questioned last week, the UN said that around 5,000 former fighters were disbanded under the programme. Yet the Observer has learned that practically none were Seleka. The lack of money meant that the entire north-east – where Seleka drew their fighters – was left untouched. "The disarmament process for the north-east could not start because no fund was available," the UN confirmed. Further pleas from the UN office in Bangui followed: the country was at a "critical juncture" and needed outside help. Tensions among the thousands of fighters amassed in the north were growing, voicing frustrations that promises made under a peace deal had not materialised. Late last year five rebel groups elected to amalgamate forces: Seleka was born.

A child soldier: Seleka coalition rebel stands near the presidential palace in Bangui. Photograph: Sia Kambou/AFP/Getty Images

Still, the international community did nothing. Interest in the CAR remained negligible, a malaise perhaps symbolised by the fact that the Twitter following for the UN office in Bangui stands at 14. Britain, along with the CAR's colonial owner France, is among those accused of neglecting the country. A Foreign Office source said he could not recall if a UK minister had ever visited the country. The British ambassador is based in Cameroon, 500 miles away. In January the Africa minister, Mark Simmonds, told parliament the UK was "active" on the ultimately ineffectual security council discussion on the CAR. What he didn't say was that the UK cuts its annual aid to the republic from £2.7m to £1.29m two years ago, though an emergency £5m package is expected to be announced by the Department for International Development this week.

Fundraising attempts have been characterised by failure. A UN request for £129m of aid received £40m. A recent Unicef emergency appeal outlined a need for £21m, but received under £6m.

Swimming against the tide is Kristalina Georgieva, the European commissioner for humanitarian aid and crisis response, who admitted being motivated by "guilt" and a sense that the world had turned its back on the CAR. Georgieva, who recently visited the country, has secured an emergency £4m aid package and says a "much more forceful contribution from the international community" is needed. "I pray that other donors will follow suit," she added. There is a darker narrative rarely mentioned by ministers or commissioners, however. Bangui-based Pascal Hounier, of the European Commission's humanitarian department, said: "Arms are flooding into the country. There were many AK47s, now there are rocket-propelled grenades and heavy weaponry. If someone wants to buy a weapon in CAR, it's very easy, $10 to $20." A study of the UK arms export licences revealed that eight months ago an unknown quantity of cryptographic equipment was sent from Britain to CAR. Earlier orders include an official consignment of military vehicles. One UK export to CAR for explosives and "bombing devices", used an open licence, meaning the actual amount of hardware sent is unknown.

Bangui, capital city but in reality resembles an over-sized village. Despite assurances that armed militia have been removed from the streets, convoys of gangs can be seen speeding through its suburbs. Photograph: Mark Townsend

Since 2005 the UK has been the fourth largest European exporter of arms to the CAR. Equally alarming is the role of Britain as the key supplier of arms to the increasingly unstable region of central Africa. Britain is Europe's largest arms exporter to Uganda and the third largest to the Democratic Republic of the Congo, both CAR neighbours. The Seleka rebellion has been boosted by large numbers of foreign fighters and warlords from Chad and Sudan. Britain is the fourth largest supplier of arms to Chad and the second largest to Sudan, both officially classified as "countries of concern" by the Foreign Office. Almost £670,000 of mainly tanks and vehicles have been sent to Chad, while the UK government last year approved £7.6m of military export licences to Sudan including weapon sight mounts. The UK has emerged as the second largest exporter of arms to the volatile, embryonic state of South Sudan – and its sole supplier of explosive devices.

To the east another threat is starting to emerge. Below the canopy of forests that smother eastern CAR, the cult-like militia of Joseph Kony is on the move. Attempts to catch the leader of the Lord's Resistance Army (LRA), once the focus of the world's largest manhunt, have become clouded with doubt. Seleka have refused to cooperate, compromising the efforts of 100 US special forces and 3,000 mainly Ugandan troops to capture the warlord, who is accused of abducting tens of thousands of children and hacking off civilians' limbs, lips and noses.

"The threat is moving north. For weeks we have seen an increase in attacks. If we have a state in crisis who cannot push back the LRA, we can expect more attacks. If CAR becomes a safe haven, then it's a real problem for the country and the region," said Hounier.

Kony's reliance on child soldiers has been mimicked by Seleka. Witnesses in Kaga-Bandoro describe youngsters involved in the killings. The concern is that a state with no functioning schools and minimal employment prospects will lead to a generation of youngsters joining the rebels. Hounier added: "More children are joining and it gets more difficult to get them back. There has been a lot of recruitment." Signs indicate that the Seleka are mushrooming into a significant force, their fighting strength of 5,000 now thought to have quadrupled.

Scores of child soldiers have been rescued and are being rehabilitated in a centre near Bangui. Papy Kabwe of the centre confirmed that every Seleka chief had an allocation of children that they used in the recent killings.

In Bangui, the atmosphere remains tense. Despite assurances that armed militia have been removed from the streets, convoys of gangs can be seen speeding through its suburbs and are blamed for looting and indiscriminate shootings. The country's infrastructure has been effectively demolished. Human rights groups say the justice system has been dismantled, the prisons destroyed. The army has been disbanded. Just 200 policemen are left in the entire country.

But it is away from the capital where the crisis is most pronounced. Malnutrition rates have skyrocketed and malaria cases have risen by 30% since the Seleka assumed control. Latest assessments reveal 484,000 people at risk of food insecurity, with more than 206,000 people displaced . Georgieva warns of a "multi-headed monster" of armed groups running amok in a state the size of France, free to plunder as they wish.

The likes of Moussa can do little but wait for the rebels to return.