The abduction of two Medecins Sans Frontieres (MSF) workers in Chad this month after a robbery at their compound near Sudan's Darfur region has again brought to the fore the question of attacks on aid workers.

Aid workers in Chad told me assaults on compounds and car-jacking on the roads happen every week and that armed bandits are their biggest worry.

But Chad is not unique. There have been at least 16 reported attacks on humanitarian workers in the Democratic Republic of Congo between January and June this year, according to statistics from the U.N. Office for the Coordination of Humanitarian Affairs (OCHA).

Fifteen of these attacks involved guns and in one case the attackers took hostages.

Worldwide, 260 humanitarian aid workers were killed, kidnapped or seriously injured in 2008, the London-based Overseas Development Institute (ODI) reported in a policy brief. This toll is the highest in 12 years and has spiked in the past three years, the study said.

But why are aid workers targets? They are supposed to be helping people.

"Humanitarian workers are seen as rich people in places where most of the population is poor," said Philippe Adapoe, the Country Director of the International Rescue Committee (IRC) in Chad.

"In general aggressors target assets and money and we have visible assets such as cars, satellite phones, money and laptops."

This may be so for robberies and muggings, but kidnappings?

The kidnapping of aid workers has soared by 3-1/2 times in the past three years -- and it is mainly international staff because they are more valuable in terms of ransom and make a more visible political statement, according to the ODI.

"Aid organisations may be attacked because they are perceived as collaborators with the "enemy", be it a government, a rebel group or a foreign power; in other cases, the organisation itself may be the primary target, attacked for its own actions or statements, or to prevent or punish the delivery of aid to populations," the ODI policy brief said.

And so humanitarian organisations often try to operate distinct from governments and in some cases avoid being escorted by U.N. forces on the ground, to maintain their independence. However it's important organisations are not misled into believing that this in itself will result in increased security for their staff, the ODI report said.

After the abduction of the two MSF staff members in the east of Chad, Mahamat Hissene, the government's spokesperson, told Radio France Internationale that his country would consider forcing all organisations to provide itineraries and to travel with armed escorts.

And so what options remain for aid workers around the world?

"Aid organisations are using a variety of strategies from using communications technology to warn each other about dangerous roads where attacks have occurred to further educating communities about their organization's mission in order to gain acceptance," Larrissa Fast, an expert on violence against aid workers at the University of Notre Dame in the United States said in an interview on its Web site.

Many aid organisations now think gaining acceptance from host communities is vital for the security of their staff members. If they are seen by everyone -- not just the immediate beneficiaries of relief -- as part of the solution of a crisis and not a group of rich folks coming to add to their misery, they may become less of a target.

But are international relief organisations doing enough to get accepted and understood by their host communities? Time will tell.

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