Sept 5 (Reuters) - U.N. Secretary-General Ban Ki-moon arrived in the Darfur region of western Sudan on Wednesday, promising to step up pressure for a political solution to the festering conflict.

Here are some facts about the conflict in the Darfur region.

* THE CONFLICT:

-- Rebels in Sudan's western Darfur region took up arms against the government in February 2003, saying Khartoum discriminated against non-Arab farmers there.

-- Khartoum mobilized 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 that at least 200,000 people have been killed and more than 2 million driven from their homes in the region since early 2003, some crossing the border into Chad, exacerbating a refugee crisis there. Sudan says 9,000 have died.

-- 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. The African Union sent 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. It was almost immediately rejected by many in Darfur who said it did not go far enough to ensure their security. A new rebel coalition has since formed and renewed hostilities with the government.

-- Ban has said that he would push for progress in peace talks with Darfur's splintered rebels. Negotiations are widely expected to be held in October.

* PEACEKEEPING FORCE FOR DARFUR:

-- The U.N. Security Council has also approved a resolution on July 31 for a new operation known as UNAMID, the United Nations-African Union Mission in Darfur.

-- It has authorized for an initial period of 12 months up to 19,555 military personnel and 6,432 international police. It will absorb the 7,000 African Union troops currently in Darfur. It is expected to cost more than $2 billion in the first year.

-- The mission will operate under a "Chapter 7" mandate on the use of force. This allows it to use force to protect itself and to ensure freedom of movement for its personnel and aid workers. Force could also be used to protect civilians.

-- The civilian head of the operation is Rodolphe Adada, former foreign minister of the Congo Republic. The force commander is Gen. Martin Agwai of Nigeria.

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