There have been at least a dozen attacks by rebels opposed to Chad’s president and skirmishes with the Chadian army in the last 12 months. After briefly occupying the southeastern Chadian towns Am Timan and Goz Beida this week, the rebels again melted away into the desert on Wednesday, according to a Chadian government spokesman.

The closest the rebels have come to seizing control of the country was in April. One month before presidential elections, columns of fighters swept across the country in less than a week and brought their fight to the capital’s doorstep. Around 200 fighters and civilians were killed in one day of fighting in an N’djamena suburb, the International Committee for the Red Cross said.

Chad’s President Idriss Deby is no stranger to attacks. A former colonel in Chad’s army, in 1989 he formed his own rebel movement in Sudan, with the backing of Khartoum. Said by analysts to be a master strategist, in 1990 he swept back into Chad and seized control of the vast, semi-desert country with barely a shot fired.

Deby convened and won elections in 1996 and 2001, but has battled waves of discontent from his own military throughout his rule. Infighting between ethnic groups, and irritation over the president’s failure to support rebels fighting his former backers in Khartoum, have fuelled the dissent, analysts say.

The rebellion picked up steam in June 2004 when Deby won a referendum letting him doctor the constitutional two-term presidential limit. Waves of defections from the army in 2005 bolstered a Chadian rebel movement in neighbouring Sudan estimated at the time to be about 3,000 strong.

In interviews with journalists, rebel spokespeople rarely express goals except kicking Deby out, but the political wings of the rebel groups have still cooked up an alphabet soup of acronyms as they chop and change their groups’ names and try to reconcile their political and military interests.

The Union of Forces for Democracy (UFD), said by analysts to be a coalition of three groups is the current forerunner, has claimed responsibility for this week’s attacks.

Rebel leaders are cagey about their strength or backing, making definitive figures hard to come by. Deby has accused Khartoum of providing the rebels with direct support. Khartoum has denied the accusation, and accused Chad of being sympathetic to rebel groups opposed to it.

Chad and Sudan signed accords in July and October pledging to expel rebels from their territories and protect their shared border.

The rebels have largely kept civilians out of their fight with the government. Civilian deaths and injuries have been low in the dozen skirmishes this year.

However, human rights watchdogs Amnesty International and Human Rights Watch, and senior United Nations officials, have said the Chad government’s preoccupation with its own survival has left it unable - or unwilling - to protect the border.

In the military vacuum, attacks by militias from Darfur have become commonplace. More than 55,000 Chadian civilians in the east of the country have fled their homes this year, according to the UN refugee agency (UNHCR).

Diplomats say it is the uncertainty about how a divided rebellion would unite and then govern the vast and extremely poor country that borders Cameroon, Central African Republic, Libya, Sudan, and Niger that makes the rebels a threat to regional peace.

Chronology of rebel attacks during last 12 months:

October 2006
- Rebels captured Goz Beida, a major aid agency hub 60 km from the Sudan border. No-one was harmed and the rebels moved on to Am Timan, before melting away into the desert, according to Chadian government.
- Heavy fighting between Sudanese rebel groups and the Sudanese army spilled over the border near refugee camps at Oure Cassoni, 400 km northeast of Abeche.

September 2006
- Government launched major offensive against rebel positions in the Aram Kolle mountains 150 km north of Abeche. 168 rebels reportedly killed in fighting.
- Fighting also reported near Adre and Birak, close to the Sudan border. No information on casualties.

July 2006
- Rebels again attack government positions at Ade in the east. Government spokesperson said attacks against army loyalists happening “incessantly”.

June 2006
- At least 20 Chadian rebels killed close to the Chad border in neighbouring Central African Republic (CAR) in fighting with CAR soldiers.

May 2006
- Presidential election day passed off peacefully despite opposition boycott and rebel threats. Deby declared victor.

April 2006
- Rebels with the United Front for Democratic Change (FUC), a coalition of 13 rebel groups, make a westward sprint across the country from Sudan and Central African Republic, briefly seizing the towns Goz Beida, Am Timan and Mongo before launching an attack on N’djamena less than a week after first crossing into Chad. Fighting in an N’djamena suburb left around 200 combatants and civilians dead, according to the International Committee of the Red Cross. Rebels repelled after French fighter jets fired warning shots near advancing columns.

March 2006
- Government said it thwarted an attempt by army defectors to shoot down Deby’s plane as he returned from a summit.
- Army and rebels clashed again near Adre; rebels claim 200 soldiers killed.
- In a second larger battle near Ade and Moudeina on the Chad-Sudan border “dozens” killed, including Deby’s army chief and main strategist.

December 2005
- Some 370 rebels and army loyalists claimed dead after 40 rebel trucks attacked Adre, a Chadian border post with Sudan 1,000 km east of N’djamena

November 2005
- Armed men attacked an army-training centre 25 km south of N’djamena and dozens more attacked two military bases inside the capital.

October 2005
- 40 government soldiers who said they opposed Deby’s re-election defected to join a Chadian rebel group operating in eastern Chad.
- Deby subsequently dissolved 5,000-strong presidential guard and analysts suggested the government had gone into “survival mode”.