The United Nations is urging the parties in Sudan's civil war to respect their cease-fire agreement and bring an end to the suffering of the Sudanese people. Peace talks aimed at ending 20 years of civil war in Sudan are being held in Kenya.

The negotiations, between representatives of the Sudanese government and rebels of the Sudan People's Liberation Army, are formally under way.

A U.N. official at the talks near Nairobi, urged the warring parties to fully commit themselves to finding a negotiated settlement for the sake of the Sudanese people.

In an interview with VOA, Martin Dawes of the U.N. humanitarian office, said Sudanese civilians are still being forced to flee their homes because of fighting in Sudan's oil-rich Unity state, in violation of a cease-fire agreement signed at the previous round of talks in October. "People are being affected," he said. "People are being forced to move from their homes. We have always said to parties that we would ask them to bear in mind the conditions of civilians, to restrict activities that impinge on the rights and on the lives of civilians. It is very sad. The only hope for the people in Sudan is for there to be peace and for these peace talks to succeed."

But Mr. Dawes found some reason for optimism. He says an agreement reached in an earlier round of talks that allows the United Nations to deliver relief assistance to rebel areas has already made a big difference. "There is no doubt that the Machakos process has also had the result of helping us in the humanitarian field," said Martin Dawes. "We have enjoyed better access to southern Sudan since October when the parties agreed as part of the peace talks that there should be unhindered humanitarian access to those in need in the field."

Mr. Dawes says about 200,000 people have received food rations and a record number of children have been immunized against polio.

Speaking at the official opening of the talks, the mediator, Kenyan diplomat Lazaro Sumbeiywo, emphasized their importance to the people of Sudan. He urged the government and rebel negotiators to be flexible and not to sacrifice the Sudanese people for their personal ambitions.

The talks are expected to last about five weeks, with a break on February 5 for the Muslim Haj.