Darfur has been described as the world's worst humanitarian crisis

More than a million people have fled their homes in war-torn Darfur amid violence by pro-government Arab militia against black African villagers.

Sudan has promised to double its security forces in Darfur to as an outside peacekeeping force takes shape.

The UN Security Council has asked for real progress by the end of the month.

Failing truce

UN aid workers said on Tuesday that government officials were continuing to intimidate displaced people to try to force them to return to their villages from camps within Darfur:

• Some displaced people who had left a camp near the Chad border to return to their village decided to turn around and go back into the camp because they felt insecure

• In another camp, the UN aid workers said there was an increased presence of pro-government militia

An independent aid agency, Save The Children (STC) USA, has reported a string of attacks in the Gennena area of western Darfur, where there is a heavy Sudanese police presence.

Displaced people have been shot at or physically attacked, even raped, while a clearly marked STC vehicle came under fire in the town's market place on Monday night.

No-one was hurt in the shooting but the ceasefire between government forces and rebels in the area appears more and more untenable, the BBC's Jihan Alayly reports from Gennena.

African ceasefire monitors working in the southern part of Darfur have also reported fresh fighting between government forces and rebels and warn aid workers to stay away.

Airlift funds

One of the few pieces of hopeful news to emerge on Tuesday, the BBC's Mark Doyle reports from Nairobi, is an announcement that the government of the Netherlands has agreed to pay for an airlift of 300 African soldiers.

DARFUR CONFLICT 1m displaced Up to 50,000 killed More at risk from disease and starvation Arab militias accused of ethnic cleansing Sudan blames rebels for starting conflict Resolution splits Arab press

The troops, from Nigeria and Rwanda, will act as a protection force for the African ceasefire monitors already on the ground, and may arrive as early as next week.

In another glimmer of hope, the UN's World Food Programme has managed to begin dropping aid to displaced people in some of Darfur's most inaccessible areas.

WFP spokesman Peter Smerdon told the BBC's Today programme the drop should immediately benefit people in the Sorbaranga area of western Darfur, close to the border with Chad.

Reinforcements

Up to 50,000 people have died since the conflict erupted in Darfur between rebels and government forces in early 2003.

Refugees say that Arab militia, or Janjaweed, followed up government air raids by riding into their villages, slaughtering the men, raping the women and looting.

Refugees accuse the government of backing the Arab militia

A US-drafted UN Security Council resolution passed on Friday has given the Sudanese government 30 days - until 29 August - to rein in the Janjaweed or face unspecified diplomatic and economic penalties.

The Sudanese army described the resolution as "a declaration of war" while the government called for a 90-day deadline instead.

Meanwhile, Khartoum has announced it plans to double its forces in Darfur to 12,000 over the next four months.

The news came at a meeting between government officials and a senior UN representative, Jan Pronk.

Mr Pronk told the BBC there had already been positive progress in implementing last month's agreement between the UN and Sudan on improving security in Darfur.