The killing of a UN aid worker on 6 December in southern Chad, some 500 km from intense fighting in the east between the army and rebels, underscored that other regions of the country are also insecure.

"Certainly civilians and humanitarian workers are under attack in the east as a direct and indirect consequence of the fighting, but there are all sorts of armed groups in other parts of the country and banditry is rife," an international security officer in Chad told IRIN.

With an estimated 90 percent of the Chadian armed forces currently fighting in the east, armed groups elsewhere can just about do as they please, he added. "We also have reports of fighters in the east fleeing to other areas with the result that the overall level of insecurity is increasing."

Crime has also been high in the capital, N'djamena, with numerous reports of roaming gangs of youth attacking people indiscriminately.

Last month an unidentified armed group stopped an NGO vehicle driving on a main street. "They commandeered the 4x4 in broad daylight and it was never seen again," another security officer said.

Ambushes

In the countryside attacks by various unidentified armed groups are common. The groups often ambush passing vehicles and attack local populations. Officials say they are often not sure if the attackers are bandits, rebels, militiamen, army deserts or off-duty soldiers.

"We know that some are employed by local political leaders in the areas and operate with impunity," Duezoumbe Daniel Passalet, the head of Human Rights Without Borders, a N'djamena-based NGO, told IRIN.

The assailants are particularly active in the east near the fighting between the rebels and the army but they are also common in the south, where international corporations have oil facilities and where the UN has camps for some 43,000 refugees from neighbouring Central African Republic (CAR).

Other attacks occur northwest of the capital around Lake Chad where smuggling of fuel from Nigeria is prevalent. "The smugglers are often armed and dangerous and frequently resort to banditry," a security officer said.

Banditry is also common in the northern desert region of Borkou-Ennedi-Tibesti known as the BET. Humanitarian organisations say that food aid trucks passing through in convoys from Libya are frequently attacked.

Another security threat populations face is unexploded landmines, particularly in the north, most of which were laid during a war between Chad and Libya in the mid 1980s. The mines have continued to kill hundreds of people in the area, according to the Landmine Impact Survey on Chad.

Rebels

Various rebel groups have bases throughout the country. Some in the north and west may have connections to the insurgency in eastern Chad. One of the oldest, the Movement for Democracy and Justice in Chad (MDJT), is made up of mostly Toubous, a largely nomadic ethnic group based in Chad's far northern Tibesti region of the BET.

The MDJT officially signed a peace deal with the government in 2002 and hundreds of Toubou fighters integrated into the army, but others have refused.

Other MDJT rebels based in the far north are accused of recently kidnapping an American missionary based in Tibesti, though other sources say his capturers' identity remains uncertain.

In the west around Lake Chad small armed groups have periodically fought government troops. The latest attack reported in local newspapers occurred in June and didn't even have a name, according to human rights advocate Passalet.

In the south there are still remnants of armed groups that had been fighting the government for decades, according to Passalet. "Only minor attacks are ongoing," he said. "This year one small group took control of a local rural area and for a short time installed its own deputy prefect to run the place."

One of the international security officers agreed that these groups are not a major force at the moment. "I also don't think they have links to the rebels in the east though some may well be among the [armed criminals] in the area."

Yet he also said that the security situation in the country is fluid and complicated. "Nobody can claim to have a true picture," he said, adding, "Anything can happen at any time at any place.”

The UN staff member killed last week was a driver working for the UN refugee agency (UNHCR) out of its field office in Danamadji, a UNHCR spokesperson said. "The circumstances surrounding the shooting are still not clear," he added.