Since March nearly 3,000 UN-trained international troops have been working with Chadian military and national police to boost security near camps housing more than 500,000 refugees and Chadians displaced from fighting in Sudan, Central African Republic and Chad.
Armed assailants have stolen dozens of humanitarian vehicles in 2009, killed a driver and government official and are holding an international aid worker kidnapped on 10 November.
On 21 December bandits attempted to kidnap two UN contractors and steal a civilian vehicle in a UN convoy travelling with a Chadian security escort.
Short on escorts
Because of eastern Chad's security classification, the UN requires the use of armed escorts for its humanitarian staff.
Laurette Mokrani, head of the UN Children Agency's (UNICEF) office in Goz Beida, 220km south of the aid hub in Abéché, told IRIN the difficulty of scheduling escorts makes it increasingly difficult to act quickly. "It used to be that if there was an emergency in the field, we could send out a team immediately, which is not the case now if we cannot get an escort."
During the most recent polio vaccination campaign in October, supervised by UNICEF and World Health Organization (WHO), requests for military and police escorts went unanswered for weeks, according to WHO surveillance expert for eastern Chad, Mohammed Mohammedi.
Troops are insufficient to provide all requested escorts, said Gavin Egerton, liaison officer for the UN Mission in the Central African Republic and Chad (MINURCAT); Egerton patrols in and near Goz Beida. "This is all a juggling act. Even if it is only one vehicle we escort, we need up to 50 persons - at least a platoon  - and four armed personnel carriers to provide sufficient coverage. We try to accommodate as many requests as possible based on our patrol plan."
MINURCAT's deputy commander, Ger Aherne, told IRIN a half-staffed force is better than no force at all. "If we weren't here, there would be a security vacuum. Who would facilitate humanitarian activity?"
The UN force's annual budget - drawn up for a planned force almost twice the size of the current one - is US$691 million. But even at the envisioned 5,200-strong military force, it would still not be enough to secure eastern Chad, said Aherne. "The area we have to patrol is 1,000km by 450km - are you seriously suggesting 5,200 troops, or even 10,000, could fully secure that area?"
French research and training group, Emergency Rehabilitation and Development (URD), noted in a working document on humanitarian space in eastern Chad: "Armed escorts cannot provide absolute protection and could even constitute...a heightened risk of violence because DIS [détachement intégré de securité, a UN-trained and financed Chadian security force] has been attacked several times."
URD director, François Gr=FCnewald, told IRIN that MINURCAT should avoid costly convoys and increase the use of small aircraft. "The banditry calls for mobility, not a heavy platoon snaking through the desert."
Aherne told IRIN that with advance notice about humanitarian operations, MINURCAT can look into preventative deployment - securing an area and placing it under watch even before the arrival of humanitarians, without requiring the mission to travel with an escort.
Impunity is the real problem, Aherne told IRIN. "The responsibility for security in Chad rests with the Chadian government.There needs to be better justice and policing."
The government's military liaison to NGOs, Yaya Oki Dagashe, told IRIN security threats have been exaggerated. "You [media] keep on saying there is a bandit taking a car, there is someone stealing something - that does not mean the country is on fire." He said in addition to the UN forces, Chadian police and military police, Chad has deployed army forces to the border. "We are doing everything we can to stop criminality."
But URD director Gr=FCnewald told IRIN impunity is widespread. "It is rooted in ethnic allegiances, organized banditry, petty crime, political insurgency and honour-based vendettas. What some see as banditry, others see as honour."