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Sudanese officials and rebels gathered for a second day of talks Tuesday, a day after Khartoum rejected a wider role for African peacekeepers despite international pressure to end violence that has led to the world's worst humanitarian crisis in the Darfur region.

The talks are a last-minute attempt at resolving the crisis before the U.N. Security Council's Aug. 30 deadline for Khartoum to disarm the Arab militia known as Janjaweed (search) or face economic and diplomatic sanctions.

Sudan's Agriculture Minister Majzoub al-Khalifa Ahmad on Monday dismissed the proposal floated by the African Union to send nearly 2,000 peacekeepers to Darfur (search), where a pro-government mostly Arab militia are accused of killing tens of thousands of black Africans and pushing more than 1.2 million from their homes.

"Nobody agreed about that [a peacekeeping force]. There was an agreement about a force to protect observers," Agriculture Minister Majzoub al-Khalifa Ahmad said. "The security role is the role of the government of Sudan and its security forces."

He said Sudan might consider an expanded African Union role later. "If there's a need, it will be discussed."

Rebel delegates at the AU-brokered talks were frustrated at the government's unwillingness to address the causes of the conflict and insisting to focus instead on aid issues, said Ahmed Tugod Lissan, head of the rebel Justice and Equality Movement (search) delegation.

His comments appeared to be a setback for the international community's hopes that the African Union could devise an African solution to the 18-month-old conflict that the United Nations has called the world's worst humanitarian crisis and others say amounts to genocide.

The 150 African Union (search) Rwandan troops now in Darfrur are operating under a vague mandate that does not spell out how far they can go to protect targeted civilians.

Rwandan officials have said the troops would protect civilians, and Nigerian President Olusegun Obasanjo (search), the current African Union chairman, offered on Sunday to have the soldiers help disarm the rebels while the government reins in the militia.

British Foreign Secretary Jack Straw toured a sprawling refugee camp in Darfur on Tuesday ahead of a meeting with Sudanese President Omar el-Bashir. Straw said the Sudanese government must vastly improve security.

He said he would tell the president that "we recognize that the government of Sudan has made progress in greatly improving humanitarian access and also in terms of the safety and security of people in the camps."

"But talking to people here, it is very clear that people are still very anxious, apprehensive and nervous about whether they will be safe to go back to the villages from which they have come," Straw told journalists at Abu Shouk, a sprawling camp set in desert and scrubland more than a mile from the provincial northern capital of al-Fasher.

It is critical the government establish "safety and security across Darfur and get the political process going," he added.

Straw said Monday his government was ready to help finance an enlarged African Union force for Darfur. British officials said an AU plan taking shape envisages as many as 1,000 observers and 3,000 troops to monitor the region.

The violence in Darfur is rooted in tensions between nomadic Arab tribes and non-Arab African villagers. African rebels rose against the government in February 2003, claiming discrimination in the distribution of scarce resources in the western provinces. U.N. officials accuse the government of trying to crush the revolt by backing a scorched earth policy carried out by the Janjaweed.

In the Janjaweed's campaign of violence against Darfur's black Africans — who like the Arabs are Muslims — armed horsemen swept into villages, killing and raping. Sudan denies backing the Janjaweed, but many accuse it of using the militiamen to put down the rebels and strengthen the Arab hold on the region.

The peace talks in Nigeria are between the Sudanese government and the two rebel groups, the Sudan Liberation Army (search) and the Justice and Equality Movement.