The United Nations Security Council is set to vote on plans to send a peacekeeping force to Sudan's western region of Darfur, officials say.

Sudan and its veto-wielding ally China appear to have agreed to the wording of the much-debated resolution.

The resolution, co-sponsored by the UK and France, would establish a force of about 26,000 troops for Darfur.

An African Union force already there has not stopped violence said to have left 200,000 dead and 2m homeless.

UK Prime Minister Gordon Brown, on a visit to the UN in New York, said he expected an imminent agreement.

The resolution would include articles under Chapter 7 of the UN charter, which would allow the peacekeeping force to defend civilians and aid workers from any attack.

Chapter 7 allows the use of "necessary action" by UN-mandated troops in an effort to ensure stability.

The resolution also calls for the start of peace talks, which are already scheduled to begin in Tanzania later this week.

Use of force

Speaking at the UN, Mr Brown insisted it was time for a change of direction in Darfur, which he described as the greatest humanitarian disaster in the world today.

"We will work hard to deploy this force quickly," he said.

"But we must be clear: if any party blocks progress and the killings continue, I and others will redouble our efforts to impose further sanctions."

The Sudanese government, which has opposed elements of earlier drafts of the resolution, is said to be happy with the current version, says the BBC's Matt Wells, at the UN.

China, a key investor in Sudan and a veto-holding permanent member of the UN Security Council, was reported to have agreed to the draft resolution.

The Chinese ambassador to the UN, Wang Guangya, conceded that the inclusion of the Chapter 7 reference was now needed, but said "we have to be precise and very careful" about when and how it would be used.

Delay expected

Under the terms of the resolution, the existing African Union troops will stay in Darfur, to be augmented by new troops.

Most of the new troops, which will have the right only to "monitor" the spread and use of illegal weapons in Darfur, are expected to come from African states.

The peacekeeping mission, to be known as Unamid - the United Nations African Union Mission in Darfur - is expected to cost up to $2 billion (£1.1bn) a year, the Reuters news agency reports.

If approved, it will come together over the final months of 2007, with the aim of being in charge of operations by the end of the year.

However, although Sudan has agreed to the UN's request for troops to enter its territory, officials say the full force will not be in place until 2008, Reuters says.

Under the terms of the Security Council resolution, the peacekeeping force cannot exceed 19,555 military personnel and 6,432 civilian police.

PHOTO CAPTION

African Union soldiers in Darfur (file pic)