NDJAMENA, 9 April (IRIN) - The Sudanese government and two rebel movements in the country’s western Darfur region have agreed to a 45-day ceasefire to allow humanitarian assistance to reach several hundred thousand people affected by the fighting.

The ceasefire is due to come into force on Sunday. It was agreed on Thursday night after two days of talks in N’djamena, the capital of neighbouring Chad.

The ceasefire was signed in the presence of Chadian President Idriss Deby and was immediately welcomed by UN Secretary General Kofi Annan. He had warned only a day earlier that international intervention might be necessary if the two sides could not settle their differences.

A spokesman for Annan said in New York: "He trusts this agreement will result in an immediate cessation of hostilities and an end to attacks against civilians, as well as full humanitarian access to all people in need of assistance and protection."

The ceasefire agreement represents a breakthrough for Chadian government mediators who spent a week trying to persuade the Sudanese government delegation and representatives of the rebel Sudan Liberation Army (SLA) and Justice and Equality Movement (JEM) to meet face-to-face.

The delegations finally agreed to sit down together on Tuesday night after the Chadian mediators proposed discussing humanitarian issues before moving on to the political agenda.

Rapid progress then followed. The ceasefire agreement was signed after just two days of intensive negotiations.

"The humanitarian ceasefire was a priority, but at the same time it includes political clauses", Ahmad Alammi, the spokesman of the Chadian mediation team, told IRIN on Friday.

The deal includes an agreement to release prisoners of war and other detainees arrested as a result of the 14-month-old conflict, to stop laying mines and committing acts of sabotage and had pledged allow the free movement of people and goods.

Darfur,an arid region one and a half times the size of Germany, has been a virtual no-go area for relief agencies in recent months as a result of Sudanese government restrictions.

According to the United Nations, 750,000 of its six million inhabitants have been internally displaced by the conflict, while a further 110,000 have sought refuge in Chad.

The ceasefire agreement commits both sides to rapidly facilitating the access of humanitarian assistance to those in need. The 45-day truce will be automatically renewed upon its expiry unless one of the parties to it raises objections.

Allammi said that the Sudanese government and rebel delegations had agreed to meet again in N’djamena within two weeks to discuss a political settlement.

The SLA and JEM are demanding a better economic and social deal for Darfur, which they say has been neglected by the government in Khartoum.

Human rights activists and relief agencies have accused Sudanese President Omar Hassan El-Bashir of using a "scorched earth campaign" in the Darfur fighting. They have accused the government armed forces and their Arab militia allies of systematically burning and looting the villages of black tribes suspected of supporting the rebel movements.

The rape and killing of civilians has become commonplace in the conflict.

The Sudanese government and rebel delegations arrived in N’djamena on March 30 to start peace talks, but they failed to meet for the following week because Khartoum objected to the presence of international observers.

Allammi said the issue was finally resolved by a compromise.

Observers from the United Nations, the African Union, the European Union, the United States and the Geneva-based Centre for Humanitarian Dialogue would attend discussions on humanitarian issues, the Chadian mediator said.

However, only observers from the African Union would be allowed to monitor the political negotiations.

The UN has described the Darfur conflict as the world’s "worst humanitarian crisis".