Sudan-backed rebels invade Chadian capital N�Djamena
From Fred Bridgland in Johannesburg

The West's worst nightmare concerning the five-year-old Darfur catastrophe in western Sudan was that the conflict would spill over into neighbouring Chad, creating regional chaos and making the Darfur situation even more intractable. The nightmare happened yesterday.

Chadian rebels, backed by the Sudanese government in Khartoum, completed a rapid, three-day, 510-mile advance west from Sudan and entered the Chad capital, N'Djamena.

Thousands of fighters from the United Front for Democracy and Change (UFDC) penetrated N'Djamena early yesterday in 300 vehicles, and spread through the city. Last night they were surrounding President Idriss Deby's palace, from where gunfire and explosions could be heard. State radio went off the air.

The French and US governments, Deby's main Western backers, told their citizens to assemble in secure locations and await evacuation. Witnesses in N'Djamena have reported looting, gunfire and explosions in the city centre. Large numbers of UN staff were among the first foreigners to be evacuated to Cameroon, Chad's neighbour to the west.

France currently has about 1400 military personnel in Chad, of whom 1200 are in the capital. It was not clear last night whether they would enter the fighting against the rebels.

Deby's 17-year rule has been marked by coup attempts and rebellions which were either suppressed with extreme violence or partially settled by expelling dissidents to Sudan or Chad's southern neighbour, the Central African Republic.

The most immediate casualty of Western efforts to alleviate the crisis in Darfur is the deployment of a high-risk European Union peacekeeping mission to eastern Chad. In Darfur, more than a quarter of a million people have died in fighting between anti-Khartoum rebels and a coalition of Sudanese forces backed by pro-government militias.

Some 3700 EU soldiers are on alert for immediate deployment along Chad's eastern border with Sudan under a UN mandate to protect hundreds of thousands of refugees from Darfur. Advance units were meant to begin deploying last week, but the mission's Irish commander, Lieutenant-General Pat Nash, said the operation is on hold until the security situation becomes clearer.

"This is one of the most unstable regions in Africa," he said. "The security situation is volatile and ever-changing. The area where we will operate is vast, the terrain is unforgiving, the climate is severe."

John Kotsopoulos, of the Brussels-based European Policy Centre, said: "This is definitely the EU's most dangerous mission so far. It will definitely have to tread extremely carefully so as not to get caught up."

The central role played by France makes the situation particularly explosive. Chad is a former French colony and last year French troops thwarted an attempted coup by the rebels. Now Paris is spearheading the EU mission, providing the most troops and equipment, and angering the UFDC and its Khartoum patron. The EU force was originally meant to deploy in November, but was held up by squabbles over funding and equipment. That first delay was a deep source of embarrassment given the EU's mandate to provide urgent relief for refugees from Darfur.

Chad's foreign minister, Ahmad Allam-mi, yesterday accused Sudan's government of launching the rebel offensive in order to block the deployment of the EU force. "Since this EU force was announced, the Sudanese government has stepped up its attacks," he said in the Ethiopian capital, Addis Ababa, where African leaders are meeting.

Allam-mi said Khartoum wanted to stop the European force from focusing international attention on what he called the "genocide" in Darfur. But rebel spokesmen cited the failure of the Chad government to begin discussions stipulated in a peace agreement signed on October 27 last year.

Deby further infuriated the UFDC by sacking former rebel leader Mahamat Nour, who had been appointed defence minister as a key part of the interim peace deal. The rebel capture of the Chadian capital also seems certain to undermine the international attempt to strengthen an African Union peacekeeping force in Darfur that is already plagued by lack of troops and equipment.

The African Union, in its first major peacekeeping operation, sent troops to Darfur in 2004, but the ill-equipped and cash-strapped mission has failed to curb the violence. The UN had promised to strengthen the mission with expertise from other parts of the world so the current 7000-strong African force would grow to 26,000, making it the world's largest peacekeeping mission.

A further complication is the recent discovery and exploitation of oil in Chad, which gives the country great strategic importance. The West will be deeply worried if it falls under the control of a Khartoum client government.

The first crude oil began flowing from Chad in 2003 along a £3 billion, 700-mile pipeline, which ends at a tanker-loading terminal seven miles off the coast of Cameroon - safe from onshore disturbances and a route to America.

The pipeline represents the biggest ever single investment project in Africa. Chad, until recently ranked one of the five poorest states on Earth, is currently enjoying a 55% annual increase in GDP. Nevertheless, more than seven million of the country's nine million people live on less than $1 a day.

Most of the oil proceeds never see Chad. They go into the coffers of US oil companies, their Malaysian partners and into the offshore bank accounts of President Deby, and his relatives and ministers.