People working in the vast humanitarian operation in Sudan's western region of Darfur are more than willing to talk about rebel attacks and the need for civilian protection, but when asked specifically about sexual violence against girls and women - reported to be rife - they fall silent.

On condition of anonymity, the employees of many non-governmental organisations (NGOs) in El Fasher, capital of North Darfur State, said sexual and gender-based violence was extremely common; one humanitarian worker said it was possibly "the most serious security issue affecting women here".

In April 2007, after attacks by Sudanese government forces and allied militia, in which at least 15 cases of sexual assault, including rape, had occurred, the United Nations High Commissioner for Human Rights, Louise Arbour, called for investigations into widespread sexual violence.

Women and girls in Darfur usually have to walk long distances, often unaccompanied, to fetch firewood, thatch or water for their families, which is when most attacks occur. The perpetrators are mostly described only as 'uniformed forces', which could mean government troops and police or any of the several rebel factions and militias active in the region.

On the rare occasions when NGOs have dared to raise the issue of sexual attacks, and have even catalogued them, the government has usually denied that the incidents ever happened.

"The government officials usually ask us to name the alleged victims, which of course we cannot do, so they say we have failed to provide evidence and continue with the denials," said one UN protection officer in Khartoum, the national capital.

"It is not in the culture of Sudan or the culture of Darfur to rape - it does not exist," President Omar el Bashir said in an interview with the US-based news network, NBC, in May 2007.

The various rebel groups operating in Darfur have also denied allegations that their soldiers were involved in sexual attacks on girls and women, and have blamed the government-allied militia, the Janjawid, for using rape as a weapon of war in Darfur.

No NGO in El Fasher is prepared to discuss the issue openly; sexual attacks are dealt with at hospitals and clinics and never reported to the authorities.

There is a clear sense that people working in the field of sexual violence are, as one UN employee put it, "terrified to death" of talking about it.

"You never know what is going to spark a reaction from the authorities; it's better to be quiet and carry on working than to speak out of turn and be thrown out of here," she said.

Government denials are not the only reason the lid is kept on sexual violence; it is a cultural taboo to discuss rape, and the victims are often shamed by their families when they report it.

But silence has its price. Women and girls in Darfur are so reluctant to report rape that unless serious injuries are sustained they would rather not even seek medical help; it also means they are unable to access post-exposure prophylactics (PEP) that could prevent possible infection with the HI virus. Despite this, organisations in the area are finding new ways to reach out to them.

Working in silence

"Our job is to treat patients who come in. We have learnt that it is not in our best interests, or the interests of the victims, to report the numbers of victims," one local doctor told IRIN/PlusNews. "We counsel the patients and advise them of their rights under the law, we treat their injuries and we send them home - the rest is up to them."

Various NGOs and UN agencies are active in the field of sexual and gender-based violence. Relief International (RI), a non-profit humanitarian agency providing emergency relief aid, and the International Rescue Committee, a non-profit organisation that works with refugees and victims of armed conflict, have several primary healthcare centres in North Darfur State.

Each RI-trained midwife is taught clinical management of gender-based violence and is able to suture cuts and administer PEP kits, mainly provided by the UN Population Fund (UNFPA). RI has also simplified and translated into Arabic the UN World Health Organisation's clinical protocols for the management of gender-based violence, making them more easily accessible to local midwives.

The UN's civilian police ensure that RI leaflets with basic information on the steps a woman should take in case of a sexual attack are widely distributed.

The African Union Mission in Sudan, based in Darfur, has a sexual and gender-based violence unit that educates local police in how to handle cases of rape, including legal measures that women can take under Sudanese law. Few women opt to take the perpetrators to court, but the hope is that a culture of reporting will slowly become part of the local culture.

A number of organisations, including the US-based Cooperative Housing Foundation (CHF International) and RI, are teaching women to make and use fuel-efficient stoves that not only benefit the environment, but also reduce the number of trips they need to make to fetch firewood, hence reducing their exposure to attacks.

Although the organisations are having some success in treating and preventing such attacks, health workers in the region say there is a clear need for government acknowledgement of the problem of sexual violence if it is to be dealt with effectively.