"The two sides will adhere to working with the African Union and the United Nations to end the conflict in Darfur and east Chad to realise stability and peace for all," a Saudi official, reading the agreement, said.
Here are some facts about the violent border triangle area.
WHICH COUNTRIES ARE IN THE TRIANGLE?
* CENTRAL AFRICAN REPUBLIC - One of the world's poorest countries despite diamond wealth, lies in the centre of Africa encompassing rainforest in the southwest to savannah in the north.
-- The 4 million population has a life expectancy of 42 years and an average income of $260 a year, according to World Bank statistics.
* CHAD - Another of the world's poorest countries, became an oil producer in 2003 with the completion of a $3.7 billion pipeline linking oilfields to terminals on the Atlantic coast. In 2005, it was ranked the world's most corrupt country in a Transparency International survey.
* SUDAN - At 2.5 million sq km (967,500 sq miles), Sudan is Africa's largest country straddling the middle reaches of the Nile. Oil in Sudan was a crucial catalyst in its bitter north-south conflict.
CONFLICT IN THE TRIANGLE / DOMESTIC TURMOIL:
* CENTRAL AFRICAN REPUBLIC - The country has had 11 mutinies or attempted coups in the past decade. President Francois Bozize, a former army general, seized power in a coup in 2003 before legitimising his presidency through 2005 elections.
-- The United Nations has estimated 220,000 people have been forced from their homes since the latest violence began in 2005.
* CHAD - A lightning assault on N'Djamena in April 2006 was launched from the east by rebels in an unsuccessful bid to overthrow President Idriss Deby, who went on to win elections.
-- In February rebels attacked the eastern town of Adre on the border with Darfur, in a raid the Chadian government said had been launched from neighbouring Sudan.
* SUDAN - Rebels in Darfur took up arms against the government in 2003, saying Khartoum discriminated against mostly non-Arabs there. Some 2.5 million civilians fled to camps in Darfur and some continued into Chad.
-- A rebel attack late last year on the Central African Republic town of Birao more than 800 km (500 miles) from the capital Bangui marked a spillover south of the Darfur conflict.
-- The leaders of Sudan, Chad and Central African Republic met on Feb. 15 and declared they would not back rebels attacking each other's territory -- repeating a pledge that has failed to stop fighting in the past.
-- Violence in Darfur has expanded into Chad, which accuses Sudan of supporting rebels launching cross-border attacks that have worsened ethnic tensions and triggered a flood of refugees. An estimated 200,000 people have been killed.
-- Janjaweed militia fighters, allied to the Sudanese army against Sudanese rebels in Darfur, have also staged cross-border raids into Chad and appear to be allied with some Chadian rebels.
-- Around 200,000 Darfuri refugees have flooded into Chad, where they shelter in U.N.-run camps.
-- Deby's government has repeatedly accused Sudan of backing the rebels, including by allowing them to strike from Sudanese territory, as part of a widening campaign of regional destabilisation. Khartoum denies the charge.
-- In the April 2006 attack on N'djamena, Chadian insurgents also used the lawless north of CAR as a staging post.
-- In a summit statement issued at the end of the gathering of leaders of Sudan, Chad, Libya and Eritrea in Tripoli on February 22, convened to advance Darfur peace efforts, Chad and Sudan had agreed not to interfere in each other's internal affairs.
- Reuters - Thomson Reuters Foundation
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