A commission monitoring a truce between rebels and the government of Sudan says Sudanese soldiers must immediately withdraw from areas seized in western Darfur during the last peace talks.

• INDEPTH:Sudan

The panel says rebel groups must not aim to regain control of the areas once the troops leave.

The statement comes from negotiation meetings in neighbouring Chad. Rebels attending those talks say they will only resume discussions if Sudanese troops withdraw.

Refugees in Darfur (File Photo)

Aid agencies estimate 70,000 Sudanese have died in Darfur's conflict since March, whether from militia attacks, disease or hunger and more than 2 million have been forced to flee Darfur since February 2003.

Meanwhile, Jan Pronk, the UN's special representative, has asked the Sudanese government and the Darfur rebel groups to observe "three days of tranquility" so the UN can begin a three-day campaign to vaccinate nearly six million children against polio.

About 40,000 volunteers have been enlisted to help the World Health Organization, the UN Children's Fund and the Sudanese Health Ministry plan to vaccinate 5.9 million children in Sudan. That's every child under the age of five.

Two further doses of the polio vaccine will be administered at six-week intervals in February and April.