April 17 (Reuters) - The United States and Britain pressed Sudan on Tuesday to allow a bigger, more muscular U.N. peacekeeping force into Darfur, saying Khartoum was not doing enough to bring peace to the violence-torn region.

Here are some facts about the conflict in the Darfur region and the peacekeeping operation.

* WHAT IS THE CONFLICT ABOUT:

-- Rebels in Sudan's western region of Darfur rose up against the government in February 2003, saying Khartoum was discriminating against non-Arab farmers there.

-- Khartoum mobilised proxy Arab militia to help quell the revolt. Some militiamen, known locally as Janjaweed, pillaged and burned villages and killed civilians. The government has called the Janjaweed outlaws and denied supporting them.

-- Experts have estimated 200,000 people have been killed and 2.5 million driven from their homes in the region since early 2003, some crossing the border into Chad exacerbating a refugee crisis there.

-- The United Nations calls Darfur one of the world's worst humanitarian crises. The United States says the violence in Darfur amounts to genocide.

* CEASEFIRES:

-- A ceasefire was agreed in Darfur in April 2004 and the African Union eventually sent nearly 7,000 peacekeepers with a mandate to monitor the peace and protect those displaced in the camps. The ceasefire has been violated frequently, with fighting blamed on government troops, rebels and Janjaweed militias.

-- A peace deal in May 2006 was signed by only one of three rebel negotiating factions. The agreement was almost immediately rejected by many people in Darfur who said it did not go far enough in ensuring their security. A new rebel coalition has since formed and renewed hostilities with the government, and the AU troops have been unable to stem the violence.

* PEACEKEEPING FORCE FOR DARFUR:

-- The African Union (AU) condemned the recent killing of five Senegalese peacekeepers in Darfur and criticised Sudan for imposing restrictions on the overstretched peacekeeping operation.

-- The attack was the deadliest against the AU Mission in Sudan (AMIS). It brought to 15 the number of AU personnel killed since AMIS was deployed in 2004.

-- AU officials say their 7,000 troops are overstretched and under-equipped to police Darfur, a region the size of France where violence has persisted despite the 2006 peace agreement.

-- In August 2006, the U.N Security Council adopted a resolution on deploying a 22,500-strong peacekeeping force in Darfur to replace and absorb African Union forces.

-- Sudan refused to let such a force into Darfur.

-- Then-U.N. Secretary-General Kofi Annan suggested a hybrid force, which Khartoum also rejected.

-- Sudan agreed to allow a "hybrid operation", involving technical U.N. support personnel, to help the AU in Darfur, the first phase of a 3-phase deployment proposed by the U.N.

-- Sudan agreed on April 16 to phase two, which involves 3,000 U.N. personnel and heavy support equipment. It has not agreed the third phase, in which at least 10,000 more troops would go into Darfur to form a hybrid force with AU troops.

AlertNet news is provided by