But Sudan's foreign minister, Mustafa Usman Ismail, raised fears that rebel groups fighting government forces in Sudan's Western Darfur region are planning to launch attacks ahead of Sunday's peace deal signing ceremony to end the country's 21-year southern civil war.

The continuing instability in Darfur, where tens of thousands of villagers have been killed in a conflict that began almost two years ago, raises concerns over whether calm can be achieved throughout the vast region ahead of the planned 10 to 12 January polio vaccination programme.

Jan Pronk, the UN secretary-general's representative in Sudan, this week urged all parties to the Darfur conflict to lay down their arms before, during and after the programme.

Polio vaccination

After meeting Ismail in the Sudanese capital, Khartoum, on Friday, Pronk said he had received positive responses of commitment to a "complete calm" in Darfur from the government while the polio programme is being held.

The UN says the conflict has been
a cause of the polio outbreak 

Pronk also said Darfur's two main rebel groups - the Sudan Liberation Army and the Justice and Equality Movement - have also shown cooperation, particularly in the volatile North Darfur state.

The United Nations cites the Darfur conflict as one factor behind Sudan's polio outbreak, its first since the virus was eradicated there in April 2001.

There have been 105 reported cases in Sudan since fighting began in February 2003, marking the third highest rate in the world.

Attack plans

Ismail claimed that Darfur rebels are plotting attacks ahead of the peace deal signing ceremony between government leaders and southern rebels in neighboring Kenya's capital, Nairobi.

"We have information that the two rebel groups in Darfur are planning to wage attacks to spoil the momentum that is now developing around the peace deal," he said without providing further details.

There have been 105 cases of
polio in Darfur 

World and regional leaders, including US Secretary of State Colin Powell, are expected to attend the ceremony, which American and UN officials hope can serve as a guide to ending the Darfur conflict.

While echoing similar sentiments on Friday, White House spokesman Scott McClellan said the Bush administration remains anxious about the Darfur crisis.

"We have some continuing concerns about the level of violence in Darfur and the need to make sure all parties are living up to their commitments and making sure that humanitarian aid is flowing freely in the region," McClellan said. 

Commitment

The vaccinations are to be undertaken in coordination with the Sudanese Health Ministry, the World Health Organisation and the United Nations' children fund, Unicef.

Ismail said his government is "totally committed" to stopping military operations so the campaign can go ahead and urged rebels to commit "for the citizens to benefit".